Hello,
Today I have used the PC for a whole day, and it worked without issues.
amdgpu.ppfeaturemask=0xfff73fff
Works great. Thank you. The reduced version with:
amdgpu.ppfeaturemask=0xffff7fff
Which should just disable PP_GXOFF_MASK did not work for me. So thank you very much for your advice. I will add it as a permanent kernel parameter to my system.
One question still crosses my mind, why is my system not working without the parameter?
I will leave the thread open for another two weeks just to be certain.