I backed it for my wife and while they have their quirks, she says they’re very comfortable and generally do the job well. Basically Bose used to make a Sleepbuds product then discontinued it. A good chunk of the product team left, bought the IP from Bose, and started this to continue the development and add lots of requested features.
My wife got a sleep headband with Bluetooth from some random Chinese company on Amazon. So far she's been pretty happy with it, though she's mostly a back sleeper. She says when she sleeps on her side, sometimes the headphone part bothers her and sometimes it doesn't. So YMMV. If you want the exact brand I can ask her, though I expect most of the brands are selling the same thing.
I actually perchance just dug up an old bluetooth portable flat speaker I got from Costco forever ago and its got great sound, can be portable/plugged in, and seems maneuverable so imma start experimenting with it. My cat loves the wooferinress of it which is interesting