This app was mentioned in 4 comments, with an average of 1.25 upvotes
There's the Spotify Companion app for Android which has a few ways of creating playlists from your existing music.
https://community.spotify.com/t5/Music-Chat/Companion-For-Spotify-available-on-Android/td-p/1337523
https://play.google.com/store/apps/details?id=com.mlpsoftwarellc.companionforspotify
Only thing that catches all the releases from my followed artists is spotify companion on android. https://play.google.com/store/apps/details?id=com.mlpsoftwarellc.companionforspotify&hl=en_US
The release stuff works, everything else is kind of bugged.
If you have an android phone u can use Companion for Spotify to get all the new releases for the artists you follow and save them to playlists.
It is the only app that really works for me and doesn't miss a release. All other features of the app are crap though :)
https://play.google.com/store/apps/details?id=com.mlpsoftwarellc.companionforspotify
Well, I saw this one on play store. I think it can help you
https://play.google.com/store/apps/details?id=com.mlpsoftwarellc.companionforspotify