[mberger]

On Windows you can open windows media player and play a silent track on repeat.

[AceyMan]

Or, the ultimate zero-software solution ... just rest your mouse on top of a running analog wristwatch; bonus points if said watch is mechanical ::grin::

[dole]

This is a great solution for my wristmouse but what about my deskmouse?

[cm2187]

Or if you can code, it's a simple flag an application can set to tell the OS it can't fire a screen saver (that flag the player uses).

https://learn.microsoft.com/en-us/windows/win32/api/winbase/...