It is not the matchmaker, trust me.
I agree personally, that the grouping up SR range should be lower than 1k SR in elos below GM (I believe). Like, I am only Gold, but I actually worked my a* off to get there from Bronze where I was initially placed. I surpassed this rank for a reason. I do not want them in my games, at all, unless I am like at the brink of losing my current SR, then I understand.
Trust me when I say, quit after 2-3 losses. Play QP, get a drink, play Arcade or whatever. It helps tremendously, because the more you play tilted the more you will lose and then blame everything else on you losing. At that point you cannot even notice all the mistakes you are doing and you are simply playing with rage.
It will only harm you in the long run.
I have personally, I think, went through all of the stages one goes regularly when playing in low elos. Through thinking how it is my teammates fault to (I do not think that I ever admitted it here), to actually buying a higher ranked account because I thought I belonged there. None of those work, at all, ever. No, nope, nada, no sir.
You feel like you are getting tilted, quit while you are ahead even if you only lost one match. Better to quit after one loss then quit after 15 while you get more and more tilted.
Trust me not every match is like that, it just looks like it because you continue to play tilted.
Stay strong random forum user. Stay strong.