3blue1brown is a great call.

I would add Applied Science and NileRed (who does chemistry experiments) as possibilities if OP likes their voices. Their content is very methodical and uniform. My cat likes their videos, which seems like a pretty good metric for this use case.

I also love vihart, who does math videos, but her stuff is a little more varied, including some music, so OP might want to evaluate her during the day before trusting her channel for sleep.

Jeremy Fielding has a great voice if you want videos about engineering and how to salvage motors out of washing machines and treadmills.

I'll consult my subscription list and add more if I find any.

Edited to add:
Carl Bugeja (electronics)
CGP Grey (mostly history)
DIY Perks (various projects)
Henry Segerman (math art)
OskarPuzzle (designs for 3d printed puzzles)
Razbuten (video games)
Sabine Hossenfelder (physics)
Stand-up Maths (math)
Steve Mould (explanations of unusual everyday things, I guess? kinda hard to summarize)
Technology Connections (as others have mentioned)
Tim Hunkin (makes weird mechanical art and explains machines)
Tom Scott (videos about unusual places and bits of history)
Two Minute Papers (advances in AI and computer graphics)

Edited again to add: Breaking Taps. This one is mostly microscopic fabrication stuff, so, various kinds of microscopes, vapor deposition, etching, etc.