brakenwagen: However I’ve already installed the update and cant go back.
edit: sometimes just re-installing the game would fix the issues.
If you have no issues installing GoG Galaxy, you can use GoG Galaxy to revert to an older version of the game.
It only offers upto the last 5 versions of the game.
Once Galaxy is installed, go into settings by clicking the COG wheel on the top left corner and under Game features - uncheck everything - especially "Auto-update games". If you want to keep everything else, you can. Make any other changes.
Click your installed games, select BG3. At the top of the screen, select the icon to the right of <Update> it looks like 2 lines 2 circles. Select > Manage installation > configure and a window will popup.
Select the version you want.
Depending on the game version it may end up re-downloading the game. So be prepared for that.
edit: once you have the version you want installed, un-install GoG Galaxy.
The ONLY other option of reverting to an older version of the game is to download the offline installers for the full game every time there is a full version. Skip the hotfix full version of the games. Just download the offline hotfixes patches.
This is only if you have the storage space to store it long term. Then you can revert to any pervious version you want.