Preferably with MO2? Does this work?
I would prefer to install MO2 as portable instance and add further mods to the game if possible

I have added few more mods from Nexusmods (just by copying to Fallout London/Data/F4SE/plugins
But not specifically MO2.

I added (some were already added by default, tho):
WeaponDebrisCrashFix.dll
SprintStutteringFix.dll
LongLoadingTimesFix.dll
HighFPSPhysicsFix.dll

Buffout was preloaded, I guess, but if not, I just added it just to be sure.