Question about MMR and matchups

how does being matched up with your teammates work???

I've been playing this game for almost over a year now, on an almost daily basis (at least five hours everytime)

Every time I go into a ranked game, I am matched with people who either just hit level 30 or have just started to try to play ranked and climb. Why does this happen? Is there a way to stop it other than suck it up and just play with a bunch of people who don't know much at all about the game? I've been trying to climb the ranked ladder for a few months now since I feel like I know a decent amount about the game and know how to carry myself and normal games have become a breeze for me, preseason I was ranked silver 3 and then from there dropped and can't seem to get back to silver and climb out. I win two matches, get matched with trolls and lose like three in a row. I even take breaks to untilt myself which honestly doesn't really even happen to begin with anyways cause losing doesn't really bother me much. I can play virtually any role with jungle not being my best but I can still go there (I prefer not to because if poppy is banned then I'm pretty much screwed, I have larger champion pools for champs in good at in other lanes) I've tried supporting, and I feel like in that role I rely wayyyyyyyyy toooo muchhhh on everyone having a brain and then if I go mid then I gotta rely on both the ADC and support having a brain which is never the case and then if I ADC then I have to rely on mid having a brain which never happens either.

I just wanna be matched up with people who know the same things as me :/