If you are using spaced repetition, or thinking about using spaced repetition with these kind of hand-crafted notes, you might be interested in Mochi[0], which uses markdown note-cards and kind of mixes the Zettelkasten concept and spaced repetition into one app.
What is the advantage of a proprietary SaaS SRS webapp as opposed to open source Anki? (note that Anki has support for, for example, LaTex, which makes collections in topics such as math highly useful).
[0] https://mochi.cards/