A native version always has potential to run better, I'm playing on a decent PC and I get 40-50 fps around the base in 0.8.0 and 120-140 outside (tried different wine and proton versions). It could be better. Doesn't UE allow compiling a linux build out of the box?
Also, can you elaborate on a "corrupted save can drop fps" thing? How do you know that's a thing, how does it work?