Final thought - fake monitor dongle needed?
No, you don't need it in general. The RTX 3060 needs it.
For all other cards you don't need it.
But if you wanna control the miner with Teamviewer you need a dummy, because it uses the output signal. Without anything plugged in you will get a black screen on Teamviewer.
I dont think that is the problem.
I use Teamviewer allways without a dummy.
It gives just a resulution at 1024 than.. thats all. (on windows)