> Honestly I don't understand why so many screens are needed, haven't felt any need for more than one in 15+ years (though I've always used max possible resolution + very small UI scaling). I even don't use multiple desktops.

I feel the same way, but I use the "medium large" scaling that macOS offers in Displays under Preferences. I do use multiple desktops, however, and using Cmd+Tab to switch between them.