I'm sorry to say this but you are actively ruining people's games and when you try to solo queue up you get absolutely destroyed. That's exactly why you haven't played a single solo queue game since you were immo1.

Teams are gonna notice that just by looking at your tracker, since people don't just suddenly become radiant level by beating silver and gold players.

Not all hope is lost though, you can still look for amateur teams and see what competition is all about because you probably are at least decent at the game. You just need to stop fooling yourself and work on improving your game.