My understanding of matchmaking in this game
First it try to give one easy game one hard one easy one hard and repeat unless you break the pattern.
If you come on a win streak it give you good players that are suppose to carry you or at least, not be heavy,
and then if you start losing the system start giving you worse teammates that are most usually monkeys and it expect you to carry cause of your rank and then it keep going until you win by the force of luck or heavy fucking 1v9 carrying and then the cycle restart.
I know cause i played like 4000 ranked games in 2 seasons and the pattern is pretty recognizable and it's why ranked is so frustrating. So yeah ranked is definitely rigged.