I am also playing through it on Series S and found the solution was to avoid using Quick Resume - fresh boot + killing any other big apps running in the background every session seems to sort the two main performance issues (texture thrashing and frame stutters even when locked to 30) and also prevents networking jank to do with pawns. Huge hassle that isn't really worth it because yeah it's absolutely dogshit on top of what is already a very janky game. Trying my best to delude myself into believing it's all metatextual commentary by Capcom.