AI_toothbrush

I want to build a linux(yes i want linux specifically or a deritive of it) smartwatch as a prototype that lasts ~24 hours. Ive been looking for chips that are small and power effient enough but most of them cant run linux. If i have a 400mah battery that gives me a power budget of about 60mw... I know its possibly because there are wearos(basically android) watches that last 3-4 days. I dont know what kind of sorcery that is but that means it consumes about 15mw??? I really do feel like im miscalculating something but i checked multiple times. Do they hibernate linux/android and run it off of another chip. I also dont know how to excecute that properly and its kind of off topic of my question. So point is linux on a ~60mw budget in s smartwatch. I want to use a mip display as i really like the look and it uses little power but if ever want a heart rate sensor in it thats even more power consumpotion. Thanks in advance i guess if a saint answers this shitstorm of a question.

Im building a flashlight and i want to test if a fan in it would be a good idea but the flashlight is really small so i would need a motor thats smaller than 1 cm preferably. I found really good ones at maxon group but unless you order them in bulk(1000+ units) they cost like 400€. So do yall know anywhere i could find them? Thanks in advance! (Edit: Im a complete baffoon and forgot to specify that preferably i would need a water resistant fan. I assumed this because bldc motors without drivers are wter resistant)