Fenix6xPro here, latest beta 17.73
But also with latest stable it didn't work for me:
I have a gpodder.net account, 3 devices in there: fenix6, AntennaPod on my android phone, gpodder-App on Fedora desktop.
The gpodder.net website does timeout all the time with Chrome, with Firefox ... it works somehow, but slow, and sometimes without reaction: I click Subscribe, sometimes that works, often not.
OK, I understand: the website is not a Garmin issue, just to draw the picture.
When I start the app on the watch and "Sync" it starts "Loading ..." . Right now it never(?) finishes. I recreated the device with a new ID in gpodder.net, adjusted that setting in the Connect app on the phone, synced the watch settings, tried again. For a start only one podcast subscribed.
I just don't get anywhere close to a working setup here ... and tend to give up on using that. Anyone with hints or tips? Maybe reinstalling the app ... just trial and error here.