Halo 2 co-op not Working

I have been having performance issues with halo 2, halo 1 ran perfectly, and halo reach runs at 1080p 60+ FPS on my computer with original Graphics on online multiplayer 8v8 and the campaign with no problems. But halo 2 only works at 20-30 FPS with the enhanced graphics in performance mode on the campaign. The textures and shadows seem to be the lowest quality, and I can’t move with it not dropping below 30 FPS. It does run somewhat well in the old graphics, 45-60 FPS, but the game freezes when switching and can not connect with my friend and play co-op. We can play halo CE, 2, 3, and reach online no problem, Halo CE campaign and Halo Reach campaign, just halo 2 campaign is not working. We don’t even care about the anniversary graphics, we just want to play the game, and he has never played the campaign.
We have tried:

  • Turning on (and off) Relay setting (this worked for CE)
  • fixed Xbox live settings before any game (NAT type and server connectivity)
  • disabled anti-cheat mode
  • both changed to performance graphics
  • starting with original cut-scenes instead of the default remastered ones
  • launching from playlists instead of individual missions
  • switching from me and my friend launching the game