So forget that last mail. Even if you rename the launcher, Steam will add it back. And it crashed again. After rechecking the logs, I think the .Net/launcher error is a followup one, because I've overlooked this:
Faulting application name: bg3_dx11.exe, version: 4.37.0.362, time stamp: 0x00000000
Faulting module name: ntdll.dll, version: 10.0.22621.2134, time stamp: 0xeee69ec7
Exception code: 0xc0000005
Fault offset: 0x0000000000033aba
Faulting process id: 0x0x169C
Faulting application start time: 0x0x1D9E57AC2338AE9
Faulting application path: F:\games\Steam\steamapps\common\Baldurs Gate 3\bin\bg3_dx11.exe
Faulting module path: C:\WINDOWS\SYSTEM32\ntdll.dll
Report Id: 43ceda13-daa9-4e35-9209-8619ce38d46f
Faulting package full name:
Faulting package-relative application ID:

I have a similar error for Vulcan, so it doesn't matter which type of graphics API I use.
Trying to run this as admin. Not hoipeful, though.