This is a rabbit hole that I followed as well. There's some good articles if you search for it.
Auto doesn't make total sense to me, but it seems originally the Romans had only the letters we know as capitals, and none of the extra characters like semicolon.
IIRC sometime in the middle ages lower case letters were added, but it's not clear to me why and how it ended up getting a bunch of different rules (eg German capitalises nouns but in English it's only proper nouns).
There are also theories out there about why our names appear in all-caps on government documents, relating to the concept of treating an individual as a 'corporation'.
