Super annoying that they don't provide straight forward numbers instead of comparisons to XR or comparisons to XS
They do give numbers. Look at the “Power and Battery” section of the official Apple “Tech Specs” page for any current model e.g.
https://www.apple.com/uk/iphone-11-pro/specs/ for the just announced 11 Pro lineup. You can probably find Apple’s pages for discontinued models cached somewhere as well if you have the time to look.
Admittedly Apple seems to quote fewer nowadays, in the old days they quoted numbers for hours of talk time, internet web browsing over both WiFi and mobile data, and even standby time at one point. I suppose that standby time is so long compared to the other numbers that, unless you literally sit your phone on your desk and do nothing with it, it’s probably irrelevant to most people and the browsing the internet figures always seemed to be pretty much the same as the figures for streaming video so I suspect Apple is trying to keep things simpler. I do miss the talk time figures a bit though.