Frames dropping for no reason, so is my sanity

So I’ve played the first missions before free roam perfectly fine. No stutter or anything. Super smooth with all graphics set to high. Suddenly the cutscene right before free roam… BOOM frame rate of a 2010 android. I’ve set all my settings to low and everything and now it runs like a 2011 android. I’ve restarted my game and computer but that did nothing. I have an AMD Radeon RX 6700 XT and it’s always run this game super smooth at high FPS. I’m 95% sure it’s the game and not my computer. Is this happening to anyone else? I literally can’t play the game. The frames are intolerable and I’m not playing halo infinite like if it was fortnite mobile.