I have fought Fallout London for 2 days and could never get it working right until now this is the vid i followed with 2 changes.

"How to Install Buffout 4 for Fallout London (And Other Performance Fixes)!" not sure if posting yt vids is allowed so just google it. In the comments it says just launch from the f4se loader after doing the fixes but that gave me no voices .Just follow the vid but launch from gog galaxy and you will have voices . It also launch in a tiny window in the top left screen but this is common for bethesda and just requires editing the falloutprefs ini file to the correct resolution your using plenty of info on the net on how to do that.

I have only played for around an hour but not one hiccup or crash. hope this helps.

Edit: I dont know why gog says ive only played london for 44 mins but i played all night last night and only had one crash during fast travel which i related to a regular besthesda crash. The game is awesome