Once I ruled out the regular 11 (as you mentioned not nearly as bright, lower resolution is noticeable to my eyes, dislike narrow phones, the grey letterboxing of videos given it cannot achieve deep blacks was not pleasant, some tinting and shadowing of the screen, etc), I gained some additional peace of mind. But that left me with my 8 Plus or my Pro Max.I'm pretty much in the same boat as you (except the recent eye exam, I need one as I'm running out of contacts!) Anyway, I'm coming from an XS Max which I somewhat got use too, and now with the Pro its pretty much hit and miss too. Not nearly as bad as the X.
I just picked up an 11 just to see if it was the same as the XR, and I have to say I'm disappointed. Of course I still get some strain with the 11 (like I did with the XR), but the screen on the 11 was not as bright as the Pro Max (even with both set to 100% max with auto-brightness turned off)and the left side of the screen was slightly dimmer than the right. Also I most certainly notice the "720p" screen, youtube videos blurry and the "fuzzy" around the text.
I'll stick with the Pro Max for now.
Where I am at now is, what degree of discomfort is worth dealing with in order to gain the advantages of the new phone. I know for many, that answer is zero. For many, no discomfort is worth keeping a phone. I did comparison shots last night using my 8 Plus and Pro Max cameras. Man, I used to think so highly of the 8 Plus photos I took but the Pro Max embarrassed it. The battery life is insane, the special audio is fantastic for watching video or listening to music without headphones. The screen, when not causing pain, is gorgeous. So, I am stumped. Another year on the trusty ol 8 Plus knowing it will still do all I need it to do, just not on the level of the Pro Max.....or keep the best phone I have ever used in every capacity but knowing at any moment I could get dry scratchy eyes.