I know the GOG page says it only works for Windows 7 and 8, but how is it in reality? I've just installed in Windows 11 and the game started up and I could see the intro. Also could get to the create character page, but I stopped there.

What is your configuration, windows version and settings? I have installed GOG version on Win11 23H2 on Dell G15 5535 (AMD 6800H+nV GF3700Ti) and natively it won't run.
I have tried several options like disabling UAC, enabling compatibilty with Win7, installing DXGL and choosing glide/DX7/software emulation
But NOTHING WORKS
I

It plays fine on my W11 Laptop, AMD setup (as if that matters, who knows). On my main PC, I have this issue where I CAN NOT MOVE consistently. I've saw a thread where other people had this problem and everybody thinks that we mean "We can't move because we haven't hit the ALT key" issue. It's something entirely different. It's like you're characters constantly get stuck and you're able to move 10% of the time. Then you just stop. Then you keep trying to move and you can for a second or 1/2 a second. Then you stop. It's frustrating as fuck. I got it to actually work for a month or 2 on my main PC but now as of tonight it's back to screwing up.

All this to say, I'd buy it from steam just for the refundability. That's what I did, then I swore I refunded it and bought it on GOG but it's still in my steam library. Oh well. It's probably the only game I've bought at the full price that it sells for in all my years of online gog/steam gaming, twice over at that.

I'm currently going through 2 hand surgeries so I can't play it on my laptop, it's just not possible. Really wanted to try that MDP.

I've experienced the "stuck" movement when using DirectX7 in the 3DSetup settings, and it only happens with NVIDIA cards. Switching to DirectX6 or OpenGL fixed it for me.

I have been playing W8 on my W11 Lenovo Legion laptop, and have never had any problems. Played the game for a very long time. Restarted many times when I decided to try a different party build, at least 100 hours of play at this point. No issues that I can recall.