There is not a single app for this. For recommendations I now sometimes use last.fm and for songs I use blackhole (even though i have 4 months of spotify premium remaining). Blackhole luckly has a song download option and I can use it with any of my media player and I can’t believe I am saying this but it has a better song recommendation then spotify.

But if you want to spam 1 artist I would say just search on spotify. you will get a playlist like "this is (artist name) ". That has good songs and you can download that playlist too. But What i do is just search it on blackhole and go to town. Download what I like and jam all the way.