[mjw1007]

That's not quite the right thing either, alas, because sometimes there's text that's legimately supposed to be "small print" where it's OK if it's hard to read. In practice setting it high tends to go wrong near small buttons.

Ideally what I want in an accessibility-settings dialog is "minimum font size that I can comfortably read", and a way for UI authors to say "this is normal body text".

Instead what we tend to get is blanket advice like Android's "use sp dimensions for text", which simply scales everything up.

iOS's preferredFontFor textStyle stuff seems like the right approach in principle, but they still seem to have the idea that if I want large body text I must also want huge headings (which is terrible, because if I have large body text I also have less space than usual).