Years ago, when Owncloud was still the only self hosted cloud solution around, the Music app used to come with an Ampache backend to connect to your music through client apps. My favorite for Android was Power Ampache, it was almost the only one, that and an extension for the really old Just Player. After a while, a Subsonic server was added to the Music app and these Subsonic clients proliferated. So, I switched to a Subsonic client, then another, and another... none was really doing it for me. DSub is great but looks dated and lacks some features, others are not mature enough, and some I just find too barebones.
Recently, Power Ampache 2 was released, and even though it's still in beta or even alpha, it already looks great and my favorite client again. Check it out if you have an Ampache server or a Nextcloud instance with music!
The smartlists feature is one of the best factors for me to recommend it. The developer is very open to comments and requests, maybe you can requests this feature in their github.