To play devil’s advocate, at least in terms of the ad reads, the way a podcast I listen to described it is essentially you go through a third party. They give you the ads you’re to read during your podcast, you either read straight off the sheet or give your own spin on it, you submit the clip of the ad read for the original company to listen to, and based on what said company thinks/the business they get from people using the promo code, said business will then send a request for another ad read for a latter podcast. It’s not exactly a “pick and choose” sort of thing, so I don’t hold what ads they get and how they’re read against them.
All the other stuff, though, that’s on them.