New Ranking System Question

So if you lose a match but you do really good in the match do you go up for that? Also will the ranking system fix the problem of matching champs when your a plat or diamond?

There’s good amount of info on the updated TrueSkill system the May Playlist Update blog, should answer most of your questions:
https://www.halowaypoint.com/en-us/news/may-playlist-updates

i think after placement, if you lose you rank down

any punishment to the people how leave the game?