I see two options for publishing to the RSS websub - used by a lot of existing web properties already

WebSub - Wikipedia

WebSub

WebSub provides a common mechanism for communication between publishers of any kind of Web content and their subscribers, based on HTTP web hooks. ...

And podping - it's attached to some web3 💩coin called hive 😬

GitHub

GitHub - Podcastindex-org/podping: A global message bus for podcast feed events.

A global message bus for podcast feed events. Contribute to Podcastindex-org/podping development by creating an account on GitHub.

Podcasting 2.0 docs

Podcasting 2.0 Podcast Namespace introduction - Podcasting 2.0