Whats going on with matchmaking?

I keep going on insane winstreaks and then insane lose streaks, usually my lose streak will be followed by very easy games where I feel as though I could have afkd and still won thanks to the team Im match withed, meanwhile when in the middle of my lose streak, I could be playing tahm kench support and somehow magically out damage the adc I`ve been trying to protect in a 30 minute game just cause they kept repeatedly jumping out of my belly and into the xin zhao that im trying to save them from??

Seriously, I`m starting to think that snowball is more of a matchmaking issue than an actual balance issue at this point, how could so many games be so onesided, and it doesnt even feel good to be on the winning team when its one sided.

Infact I feel horribly sadistic when our team is coordinated enough to group up and stamp out the 1 or 2 people struggling to carry on the enemy team while we focus them whenever we can, only for them to be flamed by their teammates for "feeding" and "having more deaths now" when its only the case because everyone is literally roaming and going out of their way to kill them because they are the only viable opposition...

That alone should be a glaring red light that something is off, when one team is coordinated and willing to support their carries, while the other team would rather flame them to Iron IV and back....