Not sure what you have against it. Works great for me. No subscription required. And if I do want to pay for ad free shows and support creators it's easy to do so.
Use whatever you like but I don't think Podcast app users are rare by any stretch of the imagination.
AFAIK the native Podcast app for iPhone is the only way to make PC-phone podcast file syncing work. This stops you downloading the same podcast file twice, once on your PC and once on your phone.
It's generally a good app. People in the tech community like Overcast, but I've always found its UI completely illogical. Apple Podcasts is organized like I'd expect a podcast app to be.
Use whatever you like but I don't think Podcast app users are rare by any stretch of the imagination.