I actually just answered this question on another post in this forum. I’ve been using a KVM to use my living room TV as another screen that I can play games / stream video / generally use my PC which is in my bedroom.
It works great in a max resolution of 4K/60hz and zero latency as far as I can tell on the USB ports for gaming controllers and mouse & keyboard. I use KDE big screen to easily navigate & open programs, emulators, steam, whatever with a controller so I don’t have to try to read tiny 4K text from the couch. I generally find disabling my monitors and enabling my TV works best.
Basically how it works is:
PC (HDMI & USB) -> transmitter -> Ethernet (CAT 6 or better) -> receiver -> TV (HDMI & USB)
The Ethernet wire only connects from the transmitter to the receiver. It does not connect to your network at all.
This is the particular one I got:
Basicolor HDMI KVM USB Extender 4K@60Hz KVM Extender Over Cat5e/Cat6 Up to 60m (196Ft), 4 Ports USB,Lossless or Zero Latency, Plug&Play(Point to Point KVM Extender) a.co/d/8Ki2lzw
Other option, if everything is in the same room you could just run some long HDMI or displayport and USB cables.