My favorite is lnbeats but its a pwa. Podcastguru is really good but its mostly for podcasts (in our case, the music podcasts which will curate songs on an hour long music show). It can be a little wonky finding specific tracks. Podverse is a good one but it's not great for discovering new music. Fountain is the cleanest, works well, and has lots of features. But I want to stick with promoting some smaller guys so we have more options.

Using rss for music is relatively new, much like nostr. But there are rss music native apps currently being coded. I know of at least 4 being developed right now.