Navidrome can do this with smart playlists. I wouldn’t call it recommendations - it’s not smart enough from that - but you can absolutely create a smart playlist that will randomly pick a given number of songs from certain genres, that are (not) recently played, etc. that will refresh every time it’s accessed
Yeah, the .view suffix always seemed strange to me. Not sure why it’s even there at all. I didn’t consciously decide not to use it either; I just am using a fork of an unmaintained Subsonic API client library and it didn’t use .view.
Even weirder is if you look at the official documentation it looks like the endpoints don’t have a .view suffix at all, and it’s only in some example requests that you even see any reference to a .view suffix. E.g. looking at http://www.subsonic.org/pages/api.jsp#getPlaylists you’d have no idea that /rest/getPlaylists.view was even an endpoint.
You could implement the schedule play music with just a cron job triggering playback via the API