Used search function and found a thread with a fix (yeah, i know). At least it worked for me on every proton version i had.
https://forums.playdeadlock.com/threads/temp-solution-found-linux-crashes-when-trying-to-enter-map-from-menu.1332/
sudo sysctl -w vm.max_map_count=1048576
or put it into...
Tried upgrading Nvidia driver from 535 to 550 and now i can spawn into the sandbox mode for up to 5 seconds before game crashes. Still no dumps, but in syslog there was this piece:
Aug 16 09:24:31 cassia steam[4726]: oject8.exe: ../src-wine/dlls/ntdll/unix/virtual.c:1876: create_view: Assertion...
