I can't open Notion on my Mac, this is the crash report on startup, hope this help thanks.

MacPro 12core, 64Gb Ram, Macbook Pro 2018 16Gb OSX Mojave Ram RME Audio UFX+, Faderport 16, Persons Quantum2, Komplete Control S49 MK2, Maschine MK3, Atom, Audio Ribera Mics, Neve Preamp 1073, Audient Pre, Outboard: Maselec MLA2, Elysia, JGR VC4, Eventide H3500. Software: Studio One4, Protools 12, Cubase, Logic, DSP-Quattro. Plugs: PSP Audio, Acustica Audio, Ik Multimedia, FabFilter, NI Komplete Ultimate, Rob Papen all plugs, OverLoud plugs, Pianoteq 6, Addictive Drums and Key, Acustica Audio Plugs. Spectrasonics Omnisphere, Stylux, Trillian. Izotope all plugs. Metrichalo Channel strip.

I examined the crash report, but nothing came to mind (which usually is the case) . . .
THOUGHTS
Among other things, I am a registered Apple Developer, and one might suppose crash reports should make sense to me; but they nearly never do . . .
Sometimes, NOTION gets a bit confused, although it's unusual and doesn't happen so often . . .
When I encounter a problem like this, the first thing I do is reboot the Mac and try it again--perhaps repeating this somewhat pointless procedure several times . . .
If that does not work, then I rename the current version of NOTION to something like 'Notion-old.app' and then re-install NOTION, with the reason for doing a rename and keeping the version that is not working being to avoid using the same storage space for the new re-install, which is based on the possibility there is a glitch in the storage space . . .
[IMPORTANT: Do not re-activate NOTION. You do not want to use more activations when doing this. Instead, you only want to get a fresh copy of NOTION . . . ]
Ensure you are connected to the web when running NOTION . . .
macOS Catalina has some increased security stuff, so this might be involved, although perhaps not . . .
If none of this resolves the problem, then call NOTION technical support and tell them about the problem . . .
I have never submitted a support request, probably because when something is not working I get very 'needy' and want instant gratification, even if it requires calling and being on hold for while . . .
However, while I have encountered a few odd problems over the past decade, I usually do experiments like the ones described (see above) until the problem goes away . . .
And I am presuming you are not running the demo or trial version and it reached the end of the demo or trial period . . .
In macOS Catalina 'System Preferences', I observe that in the 'Files and Folders' subfolder of the 'Privacy' tab of 'Security & Privacy' there is a NOTION item that has 'Desktop Folder' checked, which is because I have a Desktop folder named 'NOTION' which has NOTION scores stored in it . . .
The 'Notion.app' is in the macOS Catalina 'Applications' folder, as it should be . . .
Some applications require 'Full Disk' privileges, like 'SuperDuper! (Shirt Pocket)', which is the utility application I use to clone hard drives and SSD drives; hence it needs to be able to access everything, but NOTION just needs to access files and folders it uses for scores and so forth, although after you re-install NOTION and run it the first time, macOS Catalina will prompt you for permission to run NOTION, since you downloaded it from the web, which is normal behavior . . .
Another possibility is that you denied NOTION the ability to accept incoming connections, in which case you need to allow it, which is done somewhere else that I forget at the moment . . .
It's also important to have external stuff like an external digital audio and MIDI interface turned-ON and connected--if you are using one of these rather than the built-in macOS Catalina audio stuff . . .
Another thing you might try is double-clicking on an existing NOTION score to start NOTION, rather then double-clicking on the NOTION app to start NOTION . . .
This is all that comes to mind; and if none of it works, then call NOTION technical support . . .
Lots of FUN!
P. S. I am running macOS Catalina 10.15.3 on a 2012 MacBook Pro at the moment, and I see you are running macOS High Sierra 10.13.6, which is the current version of macOS High Sierra, hence all good there . . .
However, I am running macOS El Capitan 10.11.6 in the sound isolation studio on a 2.8-GHz 8-core Mac Pro (Early 2008), and have no problems there, either . . .
It's a bit of a stretch, but you need to be running with Admin privileges on the Mac, and you probably are . . .
If anything else comes to mind, I will post a follow-up bit of information; but at present this is all that comes to mind . . .

The Surf Whammys
Sinkhorn's Dilemma: Every paradox has at least one non-trivial solution!

Thanks for your precious suggestions, I've already followed all the steps reported before writing here, and I'm on MacOs High Sierra on Macpro 2010 intel Xeon, for daily work. Notion Crashes when I launch as reported on the crash report above. This happens after the last security update installed from the system.
In my MacBook Pro 2018 Notion performs well under i7 8th gen. With Mojave.
Hope someone will listen to this request.

MacPro 12core, 64Gb Ram, Macbook Pro 2018 16Gb OSX Mojave Ram RME Audio UFX+, Faderport 16, Persons Quantum2, Komplete Control S49 MK2, Maschine MK3, Atom, Audio Ribera Mics, Neve Preamp 1073, Audient Pre, Outboard: Maselec MLA2, Elysia, JGR VC4, Eventide H3500. Software: Studio One4, Protools 12, Cubase, Logic, DSP-Quattro. Plugs: PSP Audio, Acustica Audio, Ik Multimedia, FabFilter, NI Komplete Ultimate, Rob Papen all plugs, OverLoud plugs, Pianoteq 6, Addictive Drums and Key, Acustica Audio Plugs. Spectrasonics Omnisphere, Stylux, Trillian. Izotope all plugs. Metrichalo Channel strip.

Today I've upgraded to Mojave same problem Notion Crash under Xeon, no problems with i7 on my MacBook Pro. helpppppp

MacPro 12core, 64Gb Ram, Macbook Pro 2018 16Gb OSX Mojave Ram RME Audio UFX+, Faderport 16, Persons Quantum2, Komplete Control S49 MK2, Maschine MK3, Atom, Audio Ribera Mics, Neve Preamp 1073, Audient Pre, Outboard: Maselec MLA2, Elysia, JGR VC4, Eventide H3500. Software: Studio One4, Protools 12, Cubase, Logic, DSP-Quattro. Plugs: PSP Audio, Acustica Audio, Ik Multimedia, FabFilter, NI Komplete Ultimate, Rob Papen all plugs, OverLoud plugs, Pianoteq 6, Addictive Drums and Key, Acustica Audio Plugs. Spectrasonics Omnisphere, Stylux, Trillian. Izotope all plugs. Metrichalo Channel strip.

I examined the Crash Report again and noticed two things that might be OK, but perhaps not . . .
THOUGHTS
Both of these things might be normal and expected, but I don't examine a lot of Crash Logs; and they appeared to be curious . . .
(1) There were some calls to network stuff . . .
(2) There were calls to speech recognition stuff . . .
I continue to suggest the culprit probably is something very simple but easy to overlook . . .
NETWORK STUFF
Perhaps you have the 'Allow Network Discovery' option checked on the General pane of NOTION Preferences?
As shown in the screen capture, I check it and 'Enable ReWire', but the NOTION folks suggest checking only one, not both (at least on Windows machines); but I check both and have no problems . . .
You might try unchecking 'Enable ReWire', too . . .
If you have 'Allow Network Discovery' and 'Enable ReWire' checked, then uncheck them and see if it makes a difference; but remember to quit NOTION after unchecking and then launch NOTION afterward . . .
SPEECH RECOGNITION
There are quite a few calls (software engineer shorthand for 'running procedures') to speech recognition stuff; and while this might be quite normal, I wonder why NOTION would need to do anything with speech recognition?
Perhaps the speech recognition stuff is what macOS does when launching all applications, but perhaps not . . .
If you are running 'Dictation and Speech' or the 'Accessibility' flavors, then try unchecking or disabling the speech stuff as an experiment . . .
SUMMARY
Both of these suggestions are a bit of a stretch, but they are easy experiments, and you can revert them if it makes no difference . . .
When you do these experiments, ensure that nothing is running except NOTION . . .
And do the experiments after a fresh boot, so you are assured macOS is fresh and only NOTION is running . . .
NEW VERSION OF NOTION
After doing the aforementioned experiments, you might update NOTION and see if it resolves the problem . . .
At least then you will be running the most recent version of NOTION . . .
EXTERNAL DIGITAL AUDIO AND MIDI INTERFACE
If you are using an external digital audio and MIDI interface, then as an experiment don't use it . . .
Use the Built-In audio (Core Audio), and see if it makes a difference . . .
CALL NOTION CUSTOMER SUPPORT
The best way to resolve the problem is to call NOTION Customer Service and ask for Technical Support . . .
Alternatively, you can submit a Support Request; but I usually call if there is a telephone number . . .
Lots of FUN!
P. S. My Mac Pro (Early 2008) stopped working about three weeks ago; so I ordered a replacement on eBay from a seller in New Jersey; and today I learned the shipping service the seller uses was boarded-up and closed for the past two weeks due to 'social chaos' in the area, opening only today at which time they shipped the package with the replacement Mac Pro the seller dropped-off two weeks ago; so the replacement will be arriving later, which is fine since (a) it wasn't the seller's fault, my fault, the shipping service's fault, or FedEx's fault and (b) my Mac Pro started working after I identified the problem in a rather serendipitous way . . .
[NOTE: More correctly, the shipping service generated a FedEx shipping label, which is the way it begins. FedEx probably has picked-up the package. I have the FedEx tracking number, so I can follow the package as it moves through the FedEx system, which is good . . . ]
For the past three weeks, I have been moving everything to a 2012 MacBook Pro (13', Retina) and yesterday I remembered that I have a USB external hard drive caddy; so I pulled the internal hard drives from the non-working Mac Pro and one-at-a-time put then in the USB hard drive caddy (a.k.a., 'dock') . . .
The primary hard drive was good, as was one of the other drives; but one drive was bad and macOS Catalina 10.15.4 said it was bad and unreadable . . .
Connecting a few dots, I put the primary hard drive in the first internal drive bay slot, but not other drives; and tried to boot the Mac Pro, which diid not work as evidenced by the tiny ON/OFF status light blinking, which indicates a problem with system memory . . .
So I pulled the system memory card (was using only one at the time) and reseated the system memory strips, followed by turning ON the power and booting . . .
This time it booted, and the Mac Pro (Early 2008) is now working nicely . . .
Hooray!
The key bit of information relative to the NOTION problem you are experiencing, is that the troubleshooting strategy of removing external stuff temporarily to identify the culprit might be helpful in this situation . . .
I see that you have a lot of external hardware and devices (Native Instruments Machine, and so forth); so as an experiment do not use all that stuff . . .
Do not uninstall any of the software and drivers--just do not turn-ON the external devices and equipment . . .
If they connect with cables, you might unplug the cables, too . . .
In other words, do an experiment with just your Mac Pro, keyboard, and mouse, plus be connected to the web for licensing purposes, of course . . .
[NOTE: 'Sparkle' is the software licensing system NOTION uses . . . ]
Do experiments with the most basic configuration--Mac Pro, keyboard, mouse, and internet . . .
This might provide some useful clues . . .
If it works in the most basic configuration, then you can start adding external devices and equipment one-at-a-time, rebooting each time . . .
Lots of FUN!

The Surf Whammys
Sinkhorn's Dilemma: Every paradox has at least one non-trivial solution!