I was using the library of trantor’s .onion for a long time. I would love an Annas .onion.

Many podcast that I listen to offer and free RSS feeds when backing them directly (patreon or w.e). You can pop that feed into your favorite podcast app or script something quick. I have a similar setup to what you want that downloads webcomics I enjoy by checking the RSS feeds for new posts.

Not sure if it fully meets your needs, but what about komga?