I found how to resolve the issue, at least on my system. For context, I have no other mods installed, and I installed BG3SE by copying the DLL and JSON files. So, it was a clean install. The Lari Launcher is what prevents you from launching the game when you have BG3SE in the ...
If you still want to run from Vortex, go to Dashboard, scroll down to Tools, click on the three dots ang choose Edit. There you can click the "folder" symbol after the path in Target field and choose bg3_dx11.exe Or you can even navigate to Launcher folder (up one from bin folder...
My P4 rollback seems to be good so far, but I'm sure we'll need to update to 5 once the patch is confirmed. How do you roll back the update? I wouldn't my rolling back to patch 4 and playing will I wait on the Se update ...