My main home office has 5 monitors, and i still have to swipe between desktops regularly. I used to have 6, but two ultrawides stacked one above the other was a bit painful and I developed a back pain after a while.
My on the road setup typically involves a folding portable monitor (asus zenscreen duo, or something to that effect - that is 2x 1080p). Easily enough, and I don't really see a decrease in my efficiency.
But I sometimes do long distance flights and then I code/work on a single screen. I absolutely can do the same thing that I can do with my 6 screen setup with almost not noticeable effect on productivity as well. Could it be that the extra screens are just useless and an illusion of added productivity?