> I find it difficult to actually figure the proper position where the 27” Dell 4K (still very top notch) is just as far so that I can see it and not have to move my head left and right.

> Anything beyond this size may be OK for games, but too much space and too much windows is actually too much of cognitive load.

I find the oppposite. The goal is not to be looking at everything all of the time but to make anything I might want, from key chat channels or monitoring dashboards, to my calendar, reference docs, secondary source files, etc. to all be "glanceable" within a given context.

I find a glance, even if it requires a turn of the head, is far preferable and breaks my flow/immersion much less than having to switch windows/desktops in place. It feels much more natural to me to place things like my calendar in a consistent physical place than to have everything intrude on one place, and I find it much easier to build the muscle memory for these glances.

The biggest downside is that travelling, even with a small second monitor, completely breaks the setup.