The history of matchmaking in the last 2 years

First time I'm gonna use forum cause I feel like it GOTTA reach someone who could, maybe, fix or explain this cause maybe I'm wrong. I usualy play norm games, and been playing the game for a while now. I'm probably around plat3 caliber or something w/e. Thing is, when I'm playing alone, OR with friends. 90 % of the games, LITTERALLY 90 % of the games or more, the matchmaking is like this : 3 silver, 2 gold (me included with a gold IV placement rank to get rewards) vs 1 silver, 3 plats and a diamond. Not only is it a HUGE disadvantage in terms of mechanical talent and even more in terms of game knowledge, it has been this way for a long time now. I check the "elo" almost every game that I play.

I don't know the foums much, but I expect that many tools are around. So I'm gonna say this : I'm telling this cause I think there is no good reason for that matchmaking issue. I certainly am not a high diamond or some shit MMR that could explain this. I ADORE the game but the matchmaking is, beyond everything else, frustrating