You are counting the vertical pixels which is completely irrelevant. I understand how you got 62 percent now but it is a misleading figure.
The other poster's original post is basically correct. The XR has exactly 61% more pixels than 720p.
But all of this is rather moot since the most important determinant here is the pixel density. It's 326 ppi on the XR, just like most of Apple's non-Plus phones.
So, if you you like the iPhone 8's screen, then you'll like the XR's screen, because they have the exact same pixel density. Screen size doesn't matter.
Id rather have a lower resolution screen and have all the other features it has. Its very very similar to the XS except for the screen.
Actually, the XR has much more in common with the XS Max than the XS.
The XS is a 375x812 phone in terms of display points. However, it displays it x3 at 1125x2436.
The Max is a 414x896 phone in terms of display points. However, it displays it x3 at 1242x2688.
The XR is a 414x896 phone in terms of display points. However, it displays it at x2 at 828x1792.
For this reason, like the XS Max, the XR gets the fancy landscape views. The XS does not.
Interestingly, like the X, the XS also does not have Zoomed Display mode, so if your age-related eyesight is getting worse, the XS may be a problem. OTOH, both the XR and Max both have Zoomed Display mode.
Just hold the Max and XR next to each other when they launch and see if you can spot the difference. I can’t tell the difference between a 8 (326 ppi, = XR) and 8 Plus (401 ppi).
Yes, it’s only 326 ppi, but so is your iPhone 6. Yes, it’s only LCD, but the LCDs have always looked great and this one is supposed to be even better. OLED has its downsides too.
Conversely, for me the difference between an 8 and 8 Plus is plain as day to me in terms of PPI.
I can spot the difference, but I'm probably somewhere in between you guys. I think 326 ppi looks decent, but if I look for it, I see a difference from 401 ppi.
I don't think my wife has ever spotted the pixel density difference between her 6s and my 7 Plus though. However, if I pointed it out I suppose she might be able to spot the difference. I won't do that though, to keep her happy.

I am thinking of getting the XR for her, to replace the 6s.