Matchmaking issues (can't find matches)

Why can’t I ever find matches? I have input based and platform based matchmaking turned off, and I have every single region selection. I should be able to play with anyone on the entire planet. The only gametype I can ever consistently find matches for is Halo 3 4v4 socials. Trying to find a game for H2A 8v8 leads to 30m-1hr queue times, if at all. Most times I can’t even get a H2A game at all, which sucks because I am trying to 100% MCC and the vast majority of multiplayer achievements are for H2AMP. Also, often times I will be completely unable to get into Halo CE/2/2A matches for a long period of time, but then I add H3 to the pool and all of a sudden I get H2 matches! Same thing with server regions. When I do decide to try to play with restricted server regions, and I find myself unable to get a US-based match, I open it up to the world, and then often find US matches right after. Why is it doing this? I’ve been trying to find a comp game for the last 30 minutes now, and I can’t get into a single lobby. What gives? I’ve played MCC on and off since CE came out for PC, and I have always had these issues, but I would have hoped for a fix by now. It is very frustrating.

EDIT: Been in queue for Halo CE + 2 + 2A, Precision Slayer, Auto Slayer, Flag and Bomb, Zone Control, Action Sack and Heavies for over half an hour now. Havent grouped up with a single person. Really? Zero people in the entire world are playing these game modes right now? I’m sorry, but I just don’t believe that. Please, 343, tell me what I can do or what you can do to fix this.