I prefer to work with a single large external monitor. If my device is a laptop I keep it in clamshell mode when attached to an external monitor. I find switching applications with keyboard shortcuts and focusing on one thing at a time has improved my productivity. Using two or more monitors made it so easy for me to get distracted. To each their own though.

I use a 27” 4k monitor, in unscaled mode, but I use zoom heavily on macOS (Ctrl+Scroll Wheel) - with some extra scroll cruising setup with SteerMouse on my mouse. The lets me reduce the pixel to density to that if a much larger screen on-demand to help with my eyes a bit.