I do not know what the reason is but I have masive performance problems. in the 5.1.1 it was so I can live with but in the 5.2 with the same settings. I torture myself with 5 to 7 FPS with a 3080RTX and 32GB DDR4 Ram is impossible to work. in the UE5.1 I had at least 20 FPS
what is the problem?
Probably what you’re doing in the map 
Is it fine in the default demo level?
Neither 5 nor 20 fps is really acceptable; you should do some CPU/GPU profiling to figure out what is the problem. First run stat unit and see whether this is a CPU or GPU issue (or both) and then follow up with the appropriate profiling tools from there (e.g. Unreal Insights)
@ClockworkOcean
1.5 years i work on a city.
I started in a blank map with the UE5.0
@Krabworks
THX, is there a tutorial you can recommend?
Since it is very complex and I can make many mistakes in the settings.
I am still quite inexperienced.
If it performs ok in an empty map, then it’s just you overloading the system with too much stuff 
You’ll need to start digging into all the youtube vids on optimization.
I wonder recommend the official documentation. YouTubers etc. unfortunately often give bad advice.
This would be a good starting point: Stat Commands in Unreal Engine | Unreal Engine 5.2 Documentation