The game launches just fine and I can even create characters but as soon as the game loads, it crashes to desktop just after loading seems to be finished. OS2 runs just fine. Any ideas what I can check?

Maybe it is a performance-issue if you use the Enhanced Edition.
The original games are supposedly 32 bits, so should eat less resources.

Otherwise no idea. Try to disable every extra function and see how it goes.

I doubt it is performace related. I can run Divinity OS2 in 4k at 60 FPS.

Ok, I found the issue. It seems to be related to the resolution I tried to run the game in. It always crashes at 4500x3000 but runs fine as high as 3375x2250. So, I can't run it in my screens native resolution but I can live with that.