I’m convinced that the genre of boring Podcasts for sleeping is a large but undefined market. I listen to “in our time” and “The Guardian Long Reads” and “conversations with Tyler”.
The content has to be not so boring it’s annoying, but slow paced and open ended enough that I can fall asleep. Audio books fiction or otherwise, don’t do it for me, I guess I’m too invested and end up following along.
>>stream+(OP)
Not sure it totally fits the bill for you but for me “The Science of Everything” by James Fodor does the trick. The variety of topics plus his generally soothing voice might work?