Im Stück at 1100 rapid even though my otb ist 1550

That's a problem for me nowadays too, but here's a tip. My rating has improved a lot when I started analyzing games of grandmasters, the brain starts remembering how to attack properly, defend and etc. I think games of Bobby Fischer teached me a lot, because at his time the play was like the 1200-2000 would play. The attacks were responded by counterattacks. Really like his games. They teached me not to hope for an opponent to blunder, but also create attacks and danger that can turn the tides. Also giveaway chess helps you see what's a blunder and what is not. That's what helped me, hopefully will help you!