How often does this happen in practice and how does it happen? It's not like I google for a podcast each time I want to listen to the new episode and might get sucked into a fake search results with different ads. I add a feed to my podcast app and never touch it again (and I'm adding from a curated podcast catalogue, read: official podcasts only). Maybe if you were trolling for an ad-free feed you might find something but I've never seen what you are describing in the wild.
I built it for a local learning organization that streams their lectures on YouTube. They approached me to help them get their content over to podcast. The tool did the job and eliminated many hours of tedious manual work
I have yet to find a working paid service that does it