Getting kicked from matchmaking in game

Okay so I seem to have a unique problem and am hoping someone has dealt with this so they know how to fix it.

I can play customs most of the time with no issue, however when I get into matchmaking almost all the time and a few minutes into the game I start lagging as if I was in red bar and get kicked out of the game. My internet is fine at 20 down and I have never had any issues with other games. Its just halo MCC matchmaking, I have tried everything, hard reset my xbox, internet troubleshooting and also uninstalled the game and reinstalled. It is still not fixed!

Any suggestions or help would be awesome, thanks!

Try opening up your NAT, it is just not up to par yet but you will see an improvement if you do this.

I get the exact same issue 10secs into game I get kicked and it happens 4 out of 5 games. The other game the map just fails to load.
when are they gonna fix this? I paid money for a game that still 3 months on doesn’t work.
my NaT is open and my connection is 35m.