I'm still having the same problem (and yes, I DID update the dotnet framework). I normally play out of GOG, so the workaround to directly run the executable is different from the Steam one identified by Red Queen:
...\GOG Galaxy\Games\Baldurs Gate 3\bin\bg3_dx11.exe
1st the workaround by Red Queen is for running the dotnet installer not Bg3 so your Gog install doesn't matter
2nd you say you already installed the correct Dotnet... please see (for details on running the right installer)
https://windowsforum.com/threads/how-to-get-bg3-patch-9-to-work-after-updating.263501/as the dotnet Larian linked to is wrong... dotnet has been updated again since this issue but the 6.0.12 works and i have not tested 6.0.13 as it isn't needed to run the game
now you say you run on Gog but Galaxy has been updated to give a new Larian launcher which doesn't check the Dotnet so running a verify should download that launcher as a work around;
are you running off line patches instead of Galaxy install?
are you running on a Windows OS that isn't 10 [i.e, 8.1 or 11] are you running on a Mac?
i see two basic options here: you are running a OS that diesn't use DotNet 6.0.12 or you installed it incorrect i.e, Windows 11 is blocking access to the DotNet files... its also possible your Game files are corrupt or you just have a totally different issue blocking your game but without details who knows?