Aperantly the source code for SR2 was finally found and soon will be updated o run smoothly.

https://www.polygon.com/2019/10/14/20914451/volition-saints-row-2-steam-pc-version-source-code-finally-fixed-mod

Yeah but from what I've read they're updating it for Steam only.

They're essentially rebuilding the entire game. I'm sure it will come to GOG eventually, but it will incorporate Steam matchmaking in the multiplayer mode, so unlikely we will get that part (meh).

Hopefully the game will be able to use a bit more RAM and video RAM as the limits are affecting the game very badly now.