Hello everybody, I am slowly despairing...
After I had problems getting the VM running with an AMD GPU (5700), I was able to swap it for a Nvidia (gigabyte geforce rtx 2070 gaming oc).
At the beginning, the VM was working properly and I was able to run the VM with GPU passthrough too and I tested a game and everything worked super smooth.
Unfortunately I did a force shutdown and I could not start the VM anymore and the log quickly went up to 100%