*** WARNING *** The Podcasts app is a disaster! On both macOS 11.3 and iOS 14.5.
You'll initially show a bunch of episodes you've already played, though you can go to settings to hide played episodes. And once you do toggle that setting, you'll still likely have a ton of episodes you thought were previously played but aren't.
Even worse, forget about batch editing episodes to mark all as played. You can't even see a list of all unplayed episodes unless you get creative with a smart playlist (or what is called a station for a while now). And now showing all episodes has the most jacked up sorting order ever (groups by years in reverse, but episodes the other way). And it ignores your setting for hide played episodes.
Saved episodes is completely unreliable now. I've lost saved episodes and random other ones (already played) just randomly pop in when I try to resave anything. But wait, there's more.... it now syncs this jacked up saved stuff to other iOS devices and to Mac. So nothing is safe! Turn off the auto "remove downloaded episodes after playing" if you have relied on saving episodes in the past. If the episodes are no longer available, you will lose them!
Apple has shown for years now that it is incapable of making Podcasts better. It has been a disaster since it left iTunes. They have been more interested in getting you to listen to new podcasts than they are in making "it just work" for the ones you have.
This is the final straw for me. I will be moving to Overcast (finally). I've had it with figuring out how to deal with and work around Apple's beta quality updates to Podcasts every. single. year. DONE.