In the 8 months I have been playing Halo I have seen matching steadily decline. It’s not a lot of fun playing in a game when teamates are betraying or purposely annoying you because you got to the sniper rifle or other power weapon before they did. Also with the length of time it takes to find matches, load and black screens associated with connection problems the game is becoming less fun every day. If these problems aren’t address quickly the amount of users will continue to decline as I have seen since I started playing.
I find games fairly quickly so I think its your connection or something else like your NAT if its open its easier to find more people. If it isn’t then go to your computer and change the settings if u can.