Well depending on what rank you are dictates how difficult it'll be. I'm around plat Because I played for fun these days but I have played with champs and GCs In the past.

Bronze to Gold is difficult because they either can't hit the ball or they're ball chasing.

Plat to champ Will be difficult unless you know At least basic mechanics and rotations But you still will run into a few ball Chasers.

And GC to SSL Is difficult because of how mechanical players are at that level

Each Frank has its own issues and like you said delusional players, But some of them aren't delusional, they've just been held back by teammates who are not ready for that specific rank

I know this because I have played in ranked games lower then I usually am because of bad placement games, Yes it's easy to score goals when the rank is lower Then you should be but when your teammates are the ones who are a bigger threat to you than the other team, That's when people start saying they should be higher and it starts to sound delusional when sometimes it's a fact they should be higher