I’m currently (slowly) climbing in competitive and i was wondering if refresh rates matter? I expect the players in high elo will have a 240hz monitor but I’m unsure if that is the standard. I currently play on a 144hz monitor.

Honestly, this makes absolutely no sense. If you don't like playing with people worse than you, play on your main and stop being a pussy. Will never understand people who smurf in lower ranks then flame for people not being as good as you.