Earlier quoted context omitted.
Yeah, and I'm not terribly interested in getting into the details of how everything renders... I just want a display that works and doesn't make my eyes feel funny. The PA27JCV (which I don't expect to have back from warranty repair for 3+ weeks) looked fine, and I'm now at day 5 of using the U3223QE and it's fine. So this is my solution to the problem I guess.
Unfortunately, that might be your only solution. From what I can tell from photos of your new monitor's pixels, it has a polarizer that is of similar taste of my Dell U2414Hs, just much newer. It aims for natural reproduction, which means pixels aren't sharply defined from neighbors, and subpixels blend together. I prefer monitors like these, so I can't really argue with your choice. Sadly, due to a lot of younger ki…
And I know this is a whole lot of personal preference, but I like macOS. It works well for me. It's a good UNIX(-like?) with professional-level apps.
I support/maintain/use Windows systems for a living so I'm comfortable there as well, and I'd be mostly fine on a Linux but the lack of pro-level apps for some of my hobbies (namely, map making) and sufficiently-user-friendly equivalents for a few other apps (eg: rubiTrack, Hazel, Photos.app) is a problem.
(A bunch of years back I made a conscious choice to do less sysadmin-ing at home, even if I have to pay a bit more. It's freed up mental capacity for using computers as a means to an end vs. an end itself. And it means I don't have the flexibility of Linux or other OSS things at times, but I've been able to work within that. But I'm getting way off topic here...)