Send audio from PC to receiver through HDMI without creating a phantom screen

[CCCC]

Then - did you try the suggestion above to move the second screen corner to corner to the first one, so that the mouse (almost) cannot escape the primary screen?

Passing audio over HDMI (not ARC/eARC) requires the video signal to run, so IMO you will always have a second video screen in your system. If you cannot use linux (which of course allows setting the screens as needed, even detached from the primary screen so that the mouse has no way to escape by moving only) and have to stick to windows, then you will have to accept some workaround.

Yes, I created a custom tiny resolution for the phantom screen on Nvidia control panel and it is placed on a corner above the main screen

But the issue is not with the mouse going there (it never goes), it is with apps that start there and I cannot reach them (not always WIN+Shift+Left) works

 

[phofman]

Even if the main monitor is set to primary, do some apps open on the second monitor? Perhaps some previously stored settings?