I used to have a three monitor setup … One curved ultrawide 37" (I think) and two 24" (one on either side of the big one). The system was purely a personal setup - no professional use, though I did sometimes do maintenance on my servers from it. My setup was whatever media I was watching on the leftmost monitor, whatever game I was playing on the center, and any chat related windows (or other windows that might require supervision) on the right. I think. It’s been years since I had that setup - I might have reversed what the outer two did.

When I moved to my current home (3-4 years ago) I only bothered setting up the middle monitor, as I had no idea where the stands for the outer two were and didn’t want to bother mounting them. (Still haven’t.)

I don’t game on my PC much anymore. For what little desktop stuff I do it’s satisfactory. However, you may have gleaned from the above that I tend not to do one thing at a time. As such, now that I only have one monitor, I primarily play games in windowed mode unless I’m playing with a friend online. The windowed game goes on approximately the right half of the monitor, whatever I’m watching goes top left, chat windows mostly go bottom left (with some exceptions).

The only time I miss a multi monitor setup is when playing some games - mostly early access - that have their own ideas about the window mode. I’ve encountered a few that will respect my settings regarding resolution and mode, but insist on being dead center of the screen; some that didn’t even have a mode other than full screen; and some which would go windowed but only use the full resolution of the monitor, thus rendering the setting pointless for my use case.

Anyway, that’s pretty niche, I guess. If you don’t have a similar need one huge monitor is probably fine.