I imagine some windows update flipped a number of settings on people's machines at-least that is what appears to have occurred for me. I checked all the other tweaks I do and several not all were overridden with default values at some point.
Recently I have seen Windows reset or turn off some of these tweaks I am discussing below, I had Game DVR disabled for a number of leagues and some how it was turned back on during this last league.
I don't guarantee these tweaks will fix POE's performance for you, but they certainly seem to help my system. I think that checking some of these tweaks primarily the GameDVR could help alleviate some performance problems. I was in this boat as well, the last 3 leagues were largely OK for me but this league I kept getting pretty consistent performance stuttering unrelated to Betrayal monsters like most reported. I have seen a number of people posting about performance issues all league, pretty much: they used to run the game just fine and now they have issues. I recently upgraded some hardware in my machine and got my first M.2 NVME Hard Drive, so I have to run through these tweaks again figured I would share them.