Well, this is nifty. According to the documentation, digiKam supports using MySQL/MariaDB as a backend as an alternative to local SQLite files. Plus it documents the constraints relevant for using digiKam across multiple computers with respect to databases and collections.
On the whole, I’ve found the documentation pretty good and comprehensive. Sometimes the English feels a little off once in a blue moon. But the docs are pretty solid. I guess between 17 years of active development and growing professional grade feature sets, I should have expected the docs to be worth more than five minutes.
Good on you, digiKam contributors!