You are describing the exact same use-case as other people are using the apps for. Antennapod + gpodder.net is your podcast-as-a-service solution, where other people are using Pocket Casts.
You mainly seem to rail against people preferring a commercial solution over a FOSS solution. The reason for that is simple, people don't care about the difference and Pocket Casts provides a better user experience that just works instead of having to cobble different parts together yourself.
I just want a solution that I know is FOSS, secure and won't use my data for analytics. I have no way of knowing that from a proprietary application so it doesn't fit my use case.
You mainly seem to rail against people preferring a commercial solution over a FOSS solution. The reason for that is simple, people don't care about the difference and Pocket Casts provides a better user experience that just works instead of having to cobble different parts together yourself.