Super low FPS after Migrating Project from 5.3 .2to 5.4.4

I Successfully converted my Project from 5.3 to 5.4 today.
Everything works as it should, but i have one major problem that i cant get rid off.

The Game runs at around 20fps now (editor and playtest) before the migration it ran at 60+ fps

Looking at the GPU Visualizer, i noticed tons of “Atlas” Entries, which i have never seen before in 5.3

According to Research and ChatGPT this has something to do with Virtual Shadow Maps - Which i didnt activate in the first place.

Hay anyone got an idea what this is?