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.

3.11 was WfW, and ran on top of DOS just like 3.1 did.

NT 3.51 used the NT kernel, and (mostly) looked like 3.1/3.11 on the surface. NT 4 used the NT kernel, and (mostly) looked like Win95.

Win 95/98/Me also ran on DOS, though it was more tightly integrated than it was in the 3.1 days.

Win 2k and everything after was based on NT.