Upon logging in yesterday, my fps was complete garbage. Spent several hours trying different wine/proton versions. Eventually after some internet searching, it seems that WoW's in game graphics setting for Auto Detect graphics card wasn't actually using my graphics card. Changed this to my graphics card instead of auto-detect, and fixed immediately...
not sure exactly what changed. I think I had it on auto-detect forever with no issues, though I'm not certain, as I've never even really looked at that option in the graphics settings.
I run linux, so maybe its a wine/dxvk specific issue.