RSS is fine, and it's not going away. Adding nostr pubkey links to RSS as a podcasting 2.0 extension is the way to go. nostr:npub1arkn0xxxll4llgy9qxkrncn3vc4l69s0dz8ef3zadykcwe7ax3dqrrh43w has done some work on this which you can read here: https://github.com/nostr-protocol/nips/pull/1465/files