I am playing on steam deck oled. I try and tune for 45 fps and when actually fighting that stays pretty much locked as far as I have noticed. I have the settings on the lowest they will go with FSR balanced and it looks good enough to me. In towns the FPS drops into the 30's or even below depending on how many people are in the area but for inventory management just interacting with the NPCs it is fine even if it is not ideal. I could probably turn on dynamic resolution to help out in the towns but it does not bother me enough to bother.
Need to get to endgame maps to see how it holds up when you start juicing the content but I don't get that much time to play so it will be a while before I get there.