I was quite happily using the Podcast iOS app until iOS11 where they completely ruined it. Someone recommended that I buy Pocket Casts and I've been using it ever since. One thing that annoys me, when I go to a new Podcast I like to listen from the beginning, and Pocket Casts marks old episodes as "Played" so it's hard to go through and listen to them in order as I forget where I've gone to. Any solution for stopping…
When you first subscribe, navigate to the podcast and click on the '...' menu. If there are any episodes currently unplayed, the first menu item will be "Mark All Played". Go ahead and mark them all played, and then tap '...' again. The first menu item will now be "Mark All Unplayed".
If you're having issues with Pocket Casts marking old episodes as played when new ones come out, go into the settings (either for the whole app, or for a particular podcast) and turn off "Auto Cleanup".