Note that, as they say, "I don't have fucking brain damage; if you send us recommendations to pin posts with blatant ads for garbage affiliate sites, I will personally come to your house and stab you in the dick."
Acer B286HK 28-Inch 4k monitors. 100% worth it if most of your work is done on a computer. One of these bad mother fuckers has 4.5 times the screenspace of a 1920x1080 monitor.
Definitely requires two GPUs. As far as I know, there's no single GPU out there that can handle more than four monitors, regardless of monitor resolution.
A single GPU can drive four 4K monitors at once though? Neat.
Unexpected problem with 8 monitors: you need a good window manager. I use a macOS program called optimal layout to bounce windows between monitors and quadrants of a screen.
Depends on the card. Also depends on how many frames-per-second you're going for. A 60Hz refresh rate for four monitors is definitely doable with the right card, which works great for a work/productivity setup.
If you wanted something like 120hz or 144hz with four 4k monitors, you'd probably have a harder time finding a card that can push that many pixels at that refresh rate.
And yeah getting the right window/monitor setup is a whole process. Alt+F7 (at least on Linux) works to grab/move windows that get bumped off the screen.
