Oh No, My PC Monitor Goes Blank When Fullscreen On Endeavor OS Linux KDE Plasma!

When I first ran Endeavor OS on a new PC device. I tried to watch a video, and when in fullscreen mode, suddenly the monitor screen went blank like the monitor was dead. At that time I clicked 2x using the mouse so that the screen became fullscreen. In addition, trying to use the F11 button on the keyboard is also the same. The point is when entering fullscreen mode, the monitor screen immediately…