Op is one of those people who find it easier to read when words are spelled correctly and don’t shoehorn in a throwback letter that hasn’t been used in English for centuries.
Notably, there is only one language that still uses the thorn. Icelandic has less than 500,000 speakers worldwide. Also notably, Icelandic is not English and whether or not you’re bilingual doesn’t excuse poor spelling skills.
It’s very easy to miss if you aren’t looking for it. But if you keep an eye out, you’ll see most clocks with roman numerals do this.
Such a small max length is a good indicator they aren’t handling passwords correctly. A modern website should be able to send and hash kilobytes of text without the user seeing a significant delay. Having a max size like this sounds like they are storing the password as text instead of a hash.
Or some dumb project manager said passwords longer than 24 characters look bad in the UI and wanted the limit.
None of those languages have thorn in their modern alphabets.
And every example you pointed out is valid English. You should probably learn it if you are going to nitpick other people’s grammer