You are being vague.When I suggested here a couple of weeks ago that PCs should never be part of a true hi-fi system, I received a load of unsubstantiated and hostile rebuke from some here!
I agree with you - PCs are not built with solely audio in mind and therefore should be used only for control purposes. Load your control app onto PC, iPad, phone, or whatever, but ensure the audio signal remains from start to finish within equipment designed solely for audio.
I'll await more hostile reaction - presumably from those who use their PCs for streaming, DAC, etc. I'll stick with "proper" hi-fi!
Taking you by your words:
Nothing allowed within the listening room but the hifi-system.
No phones, no tablets, Monitors... no network equipment.
Just you and your hifi-system.
That means, all your files are on that system, and you cannot use anything like a PC to navigate through your stuff etc.
The irony is that many of these run Android...