Matchmaking/cheating?

Hi

I came across 2 players with Greek names in 2v2 matchmaking who did the following:

They both play very well. 1 is conqueror in teammatchses the other gold 1. They both play like diamond or above I feel.

I don’t care for a random smurf but this is something different.

I looked them up afterwards. The conq player only plays with 2 friends. The gold player regurarly ques with others but only loses. I think it’s just to boost the other players stats. Because together they almost win all matches.

At one point I feel like matchmaking sucks. As plat players we regurarly come across diamond or conq players way above our ranks.
On the other hand I feel like these guys manipulate the matchmaking and scoring system. Because they lower the avarage score and get more wins on 1 account which feels unfair to other players.

What can we do about this?