The "unplayable lag" in my co-op run was actually my roommate's TV setting
My roommate and I put 60 hours into a co-op game and he kept blaming the servers for lag on every boss fight, but last weekend I finally watched him play and his TV was in "cinema" picture mode the whole time. That mode adds like 100ms of input delay, so his dodge rolls were hitting a full beat late and we wiped on the same fight 14 times. I switched it to game mode and suddenly he was parrying like a pro, and he still thinks the devs pushed a stealth patch. Half the "broken netcode" posts on this game's forum are probably people playing on a 55 inch screen with motion smoothing on. Did anyone else figure out their setup was the real bug, not the game?