Just because everybody needs to read doesn't mean everybody needs custom web fonts, and just because some webpages are hard to read doesn't mean web fonts would improve them.

For most webpages I want to read these days, I hit "reader mode", which uses the same exact font for every article, and that makes it more readable.

For example, this very webpage (which is ironically about improving typography on the web) uses custom web fonts, and (as you note) this makes it less legible!