This is my Problem:

I didn't use Hermes all the time and my app was super, super fast (2 Sec. Start-up time). Now that I added React Native Reanimated I had to enable Hermes and now the app is super slow:

Nearly 5 Seconds is horribly is you consider that I had 2-3 Seconds once. Now if I deactive Hermes the app is fast again but some libraries, based on rn reanimated, don't work anymore.