There are a lot of AI narrator services you can use to create and record custom podcast. There is one called narrationbox which I specially use to create Audio Books from ebooks. You can use it to record custom podcasts as well.
I also had the same issue with these. So i started using these AI narrator platforms. These are generally used to convert ebooks into audio books but i used it for pronunciations and accents. I used the one called Narration Box. Here is the link- narrationbox.com
Was listening to Data Lake architecture last week. Ran out of my audible credits early this month so used this website, I think it was called Narration Box or something to turn the ebook into audiobook. Not to shabby but it was TTS at the end of the day, so I guess it almost works. The book's pretty great though.