I valued hard CC back when I was in silver. Currently playing in silver for Flex to work on
and its pretty chaotic how mismatched teams can be in the que.
If your not steamrolling games. its a grind. Mitigate a unneeded loss. Try to keep teammates focused on a win or from tilting to badly. If you can maintain a wr over 50% you will slowly gain MMR on your account and then get into a range of play your teammates are slightly better... but your always going to have lost matches or free wins that are low fun.
The best advice I have is try to understand your playpattern well. What do you enjoy and succeed playing. Not just a champion but the style. Aggressive, defensive, OBJ focused. What mechanics come naturally to you. From there you can then start looking at the champions in the game and zero in on the ones who are not just "fun" or "good" but both.
If you play some one well + enjoy it, take losses as part of the package and aim to just self improve off them rather then trip about the RNG. It helps a lot. Tiers are inherently inaccurate measurements because they don't realistically account for System uncertainty on an account. Why the hidden MMR values are used by MM.
But do keep your WR in mind. Keep tabs on games that felt winnable and ones that are just a mismatch. if you constantly lose in what feels winniable, its likely an issue for you rather then RNG teammates.
One challenge I give folks from time to time, Go play a custom game. Fill your enemy team with Advanced ai and your team with beginner Ai. Can you win? If yes. Then Remove 1 bot from your team. make it a 4v5. Can you win?
Its not the best system due to different classes but if your struggling to beat AI when disadvantaged you probably don't have much hope to beat Players when your disadvantaged. Playing from behind and knowing where and how to pull weight is good skill.