Maximize to FullHD in a 4K screen

[Holysword]

I'm wondering if there is any trick for doing this very bizarre thing...

I have a 4K display. Sometimes I wanna just turn on my TV (connected to the PC through HDMI) and watch things there instead, in 1920x1080, not in 4K.
What I have been doing now is having the X Screen to display the TV on the side of the 4K Display, and then I have to drag windows to the TV Screen. It is not very ideal because I have this weird "portion" of my virtual screen which is largely unused and creates some confusions for some applications which try to guess how/where to place things in your screen.

Another solution would be to actually just clone the 4K screen. But since the TV is only 1920x1080, that would mean just one quadrant of the 4k shows in the screen. That wouldn't bother me, except that I cannot put my movies in fullscreen mode, unless I'm willing to watch only one quadrant of a movie.

Is it possible to trick windows in general (mostly chrome) to "think" that my screen is just as large as one quadrant, and have it go fullscreen mode in just that quadrant?
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"Nolite arbitrari quia venerim mittere pacem in terram non veni pacem mittere sed gladium" (Yeshua Ha Mashiach)

[hhfeuer]

I dont think I fully understand your issue but maybe you should look into xrandr scaling.