I had the same issue, tried a gog galaxy install didn't work, steam install also didn't work. Always had the same warning in Larian Launcher even though I never installed mods and verified the files a few times. What worked for me was browsing to BG3 installation folder and launching bg3.exe, this bypasses the larian launcher and I don't think you can play online with it but it works fine for me. Relaunched game 3 times and no problems. bg3_dx11.exe still freezes for whatever reason so I don't use that.
