I know my previous nostr-based payment metadata solution didn't really get adoption from other PC20 apps - so me and @dovydas@podcastindex.social have come up with a much simpler solution for LNAddress payment metadata:

https://github.com/Podcastindex-org/podcast-namespace/pull/734

TLDR - we use the BOLT11 invoice description field to add a rss::payment prefix along with a URL that returns the full metadata in a x-rss-payment header.

From today all LNAddress payments sent from Fountain will use this metadata approach - so feel free to start testing!