Jeff-Relf.Me @. wrote:
Is there monitor that doesn't flash "No Video Input"
after you (supposedly) put the monitor to sleep ?
it should be optional.

I've no way of knowing which monitors don't do that, if any.

Multi-sync monitors have an OSD (OnScreenDisplay).
They have a tiny processor. They analyze Hfreq and Vfreq
and refresh and that kinda stuff, to determine if
"the inputs are within range". The OSD warns you
if you are driving signals which cannot be represented
on the screen.

They stopped making fixed-sync monitors long ago.

Why not crack the manual that came with your
fancy monitor, and see if it has a section about
the OSD, with what options are available.

Paul