Crash early in startup before first visible action/window creation.
On Proton 5.13 the Anti-Cheat seems to catch on to something and aborts the launch with a Error message instead of crashing:
Reproduction
Normal app launch from Steam
Additional remarks
Disable Steam Overlay, otherwise the game takes Steam with it when it crashes.
The game seems to use "Anti-Cheat Expert" as Anti-Cheat and Anti-Tamper, I could not find any other report referencing this system or one of it's components called "SGuard.exe".
Compatibility Report
System Information
I confirm:
Proton Experimental bleedingedge Log: bleedingedge-steam-1913730.log
Proton Experimental Log: steam-1913730.log
Proton 7.0 Log: proton70-steam-1913730.log
Proton 6.3 Log: proton63-steam-1913730.log
Proton 5.13 Log: proton513-steam-1913730.log
Symptoms
Crash early in startup before first visible action/window creation.
On Proton 5.13 the Anti-Cheat seems to catch on to something and aborts the launch with a Error message instead of crashing:

Reproduction
Normal app launch from Steam
Additional remarks
Disable Steam Overlay, otherwise the game takes Steam with it when it crashes.
The game seems to use "Anti-Cheat Expert" as Anti-Cheat and Anti-Tamper, I could not find any other report referencing this system or one of it's components called "SGuard.exe".