Just finished a warzone game that was non-stop stutter. At first it was fine and then it deteriorated a few minutes in. At first i though maybe it was that frame drop thing i’ve read about or maybe my internet. But looking at the after action report 25 players came and went. This was easily the worst game i’ve had in this game. Until then i haven’t had to many problems.
Try another game or 2 online (different ones of course) to see if you have the same issue. Might just be something you have to but shouldn’t deal with if you want to Halo.