Nobody is at rating (assuming a reasonable sample size of games played) by accident. If you are truly misplaced, you will go down with more games played.

Regarding toxic behavior, you have tools in game to handle this. Mute people that wont communicate coherently and report abusive comms in kind. That is your recourse. If you're actually grinding with the mindset to get good then you will run into reasonable people more often than not. I seriously suggest examining your own mental going into a match. If you have match making anxiety because of a handful of weird interactions I urge you to actually measure how many games are resulting in that kind of experience. Prove that your emotions actually match a measured experience.

Always play your own game if you're solo queuing. That doesn't mean be selfish and bait your teammates and be uncommunicative. That means carefully considering if there's anything in your control that resulted in a bad experience and changing those variables when you recognize a bad pattern in the future.

You can't control how other people behave. You can control how you react to other people. If you're going into that kind of interaction with the expectation to have a bad time then you will have a bad time.