IIRC a further complication in German is that the dots in ä/ö/ü started out as a small "e" on top of the letter, whereas the dots in most other Latin-based lang

IIRC a further complication in German is that the dots in ä/ö/ü started out as a small "e" on top of the letter, whereas the dots in most other Latin-based languages (e.g. in English ë) are mere accents. This is why the "expanded" versions of umlauts are still ae/oe/ue. The alphabet I learned as a German child in the 1990s certainly didn't include the umlauts or eszett, nor did it acknowledge them as distinct letters. The alphabet had 26 letters, the umlauts were counted separately and the eszett was always the odd one out (often considered simply a special orthographic variant of the double-s). So to that extent, the umlauts and eszett are definitely less "letter-like" than the Nordic å or ø which are proudly included in those countries' alphabets.