Something different. All zaps for Wavlake content go to Wavlake. Their backend does the splits.
I believe @fountain_app does the same thing
I know their player implements the RSS value split spec: https://github.com/Podcastindex-org/podcast-namespace/blob/main/docs/1.0.md#value-recipient . I'm not sure how their new Nostr integrations work, but it's probably on the backend like you mentioned.