Something switchers may want to consider, it seems each iPhone renders text/pages very differently and it's almost counter-intuitive. My phone progression is iPhone 7 > XR >XS. I've never had the Plus so I can't comment on that one.
But when I moved from the 7 to the XR, as others have noted the screen is really great. But for some reason, even though the XR had a much larger screen than the 7, text appeared smaller, and harder to read.
When I got the XS, I thought that issue will be magnified even more making the reading experience worse (going from the larger 6.1 to the 5.8) but to my surprise the XS rendered text and pages larger than the XR, in just about all the apps (messages, Safari, Email etc...) and it was much easier to read. I still don't know what's going on with this, it doesn't quite make much sense. Is it an aspect ration thing? My guess is it's software-related, but why would Apple intentionally make the reading experience and page rendering worse on a larger screen than the smaller ones?