I'm getting this same issue. I have attempted to repair the install through Steam, re-install through Steam, restart the workstation, and re-install on a different drive. The launcher appears to start up, but then crashes after about 2-3 seconds. According to my Event Viewer, this is what I'm getting:
Faulting application name: LariLauncher.exe, version: 1.0.0.0, time stamp: 0x5f1757ad
Faulting module name: coreclr.dll, version: 4.700.20.41105, time stamp: 0x5f3397ec
Exception code: 0xc0000005
Fault offset: 0x0000000000191dcb
Faulting process id: 0x3cc4
Faulting application start time: 0x01d6d71e430c9273
Faulting application path: D:\SteamLibrary\steamapps\common\Baldurs Gate 3\Launcher\LariLauncher.exe
Faulting module path: C:\Program Files\dotnet\shared\Microsoft.NETCore.App\3.1.8\coreclr.dll
Report Id: 42881b5f-5ffb-4151-a6ff-0d0df06d86eb
Faulting package full name:
Faulting package-relative application ID: