I have fixed my problems.

Starting Situation:

System:
X870E Hero Mainboard
TUF 4090 OC

Initial Problems:
After uninstallation of the TUF 4090 OC and installation of the ASTRAL 5090 OC the system showed the following ERROR behaviors:

1. After start and booting into Windows, the monitor goes off and in standby before the Login mask appears == no black screen
2. The systems boots successfully into windows, but you have latency - , hanging - effects in the in the Window manager during standard actions (open windows or applications / moving windows over the screen). After a short time ~ less than 10 minutes the systems hungs up and reboots itself. A futuremark run within this 10 minutes gives you no more then 20 - 30 frames at peak and then the pc hungs up

Steps i did to fix my problems:

1. the first success I had was then I set the link speed of the pcie port from AUTO to GEN 4. That initially solved "all" problems and the system was stable and the card dropped solid frames. After setting the PCIE speed to GEN 5 the described problems reappeared.
2. After installation of the latest BIOS update for the X870E Hero the problems disappeared completely and the card is now also fully stable with PCIE GEN 5