I really don't know much in this area but this seems to be more of a posture thing. A physiotherapist told me he only uses laptops because apparently that's the best combined with the right table and chair due to the tilted, low screen.

In my experience he's at least not completely wrong, but in the long term I still aim to try a standing desk to mix it up, sooner or later sitting in general feels wrong when I overdo it. And I just prefer a single large screen. Enough to fit two windows beside each other with enough space for any situation.