Nothing is for everyone, but if you have any level of interest in learning world history, then Dan Carlin's Hardcore History podcast is an absolute must. His deep dives into topics like World War I, the reign of Ghengis Khan, the fall of the Roman Empire, World War II's eastern front, and more, are long, thorough, and well-paced. They make long drives or plane rides something to look forward to, which is a huge accomplishment!
Obviously the baked-in Apple podcast app is terrible. For a long time I was a Downcast user because they were the first app I heard of with the now ubiquitous speed up feature. However, Overcast has a few other niceties (volume normalization, dead air removal, and overall cleaner speed-up) that make it a runaway winner.
Sadly, Overcast does not support importing premium podcasts that require authorization. This is a bit of a drag, and had me listening to the entire Ghosts of the Ostfront series on Apple's podcast app. However, I then realized something very simple that got me back into Overcast!
This is as low-tech as they come, so prepare to be underwhelmed. Once I paid the $60 for Hardcore History's entire archive, I had a URL guarded by basic auth that my computer and Apple's podcast app knew how to open, but not Overcast.
All you have to do is visit the RSS feed link in your browser, download the raw page contents into a file on your computer, upload that somewhere publicly available (but secret!), and point your Overcast app at the new URL. Viola -- Hardcore History in Overcast!
Dan Carlin is a hard working guy who, oddly, gives away his best and most recent content for free. That said, I was more than happy to pay for his archives because it's money he's earned manyfold over. If you use this hack, please do not make the URL publicly available to anyone other than yourself. Premium content is worth paying for!