The default setup I've been using for years is to dedicate a desktop to emacs, break it into 3 windows horizontally, and then each of them fluidly switches between being full-frame in its bit and being cut in half. That gives me up to six contexts to operate in at once, though it's certainly some sort of code smell to need that many for some particular task! But 2, 3, and occasional dips into 4 are pretty common, as well as having something open for other reasons.

This is also part of why I try to mostly, but not super pendantically, maintain the discipline of keeping lines under 80ish characters most of the time. Occasional spill is no big deal but constant spill gets hard to read in this context.

Partially this is just out of habit of many years, but lately it's becoming an actual advantage. My most recent project has me diving through multiple codebases, none of them in the same language; I've followed some interactions through Perl, Java, PHP, and Typescript codebases in quick succession. Both having the multiple contexts, that I have years of muscle memory using, and not needing to load up separate IDEs for each of them has turned out to be really advantageous. Emacs may not be the "best" at handling any one language but I don't think there's much better at trying to handle all of them simultaneously.

I do the same thing in Vim, which has turned me into the "please wrap to 80 cols" person, which I'm completely fine with haha.