Matchmaking/MMR cannot be working as intended

I don't understand the matchmaking in this game. I'm assuming (correct me if I'm wrong) that MMR is back on because I can't switch killers after readying up, and simply put its not working. I just bought Plague and have been playing with her for about 2 days now, and I'm really bad with her. Despite that, All of my matches have been with at least 1 decent player. I have not gotten more than a single kill per game, possibly none at all so far. In short: I HAVE NOT BEEN PERFORMING WELL. Regardless, my last game was against a bunch of red rank streamers. Why am I playing against these people if I can't even do moderately well against bad players?

The other thing that I think shows the Matchmaking is completely broken is my matches as Legion. The system thinks I'm a terrible Legion apparently despite him being easily my best killer. I consistently 4k or 3k and hatch with him , even against better teams/players, but it still pits me against babies every other match. If matchmaking or MMR was actually working it should be the other way around. Am I crazy or is this pretty much the norm?