There can be a lot of variability between apps. Fountain usually takes the longest. Realistically, it should be like 20 minutes. When it's taken longer than that (in my experience) there was an issue with how it was uploaded.
How long after uploading an XML to podcastindex.org will the song appear in apps like Fountain? nostr:npub177fz5zkm87jdmf0we2nz7mm7uc2e7l64uzqrv6rvdrsg8qkrg7yqx0aaq7 nostr:npub19ha7tju4teqp3dmwv4p28wrcy9zd6h6hxkg5mwvjrlfycweazpkse2q0fa
Discussion
Your mileage will vary depending on what you're using but the search tab in LNBeats.com is what I use to know if music is in the index.