I use 2 screens for that work
In this (my) case I have space above my primary monitor, but not to the sides, and in that space is presently the secondary monitor, long dimension vertical. But... that ends up ergonomically being a little flaky, largely I suppose because the bottom of the secondary monitor is separated from the top of the primary monitor by the top of the work desk / “hutch”. So, if I want to compare documents or, say, two graphs, it just doesn’t work so well. For that I prefer the two items displayed as closely as practical / side by side. With the right video output I could put TWO medium size (24”-27”)monitors up above the primary monitor, but, a single 43” 4k makes a lot more sense to me...
90% of “work” time my primary monitor is all I need. But there is that other 10%. And, some evening / weekend I might want to lean back and watch some non-work! :-)
To clarify: “in that above space”