Do you already sleep with a wrist watch on? I got one for the same and realized I can't stand sleeping with something on my wrist. Also realized if I want to use it for anything else throughout the day, that's the best time for me to charge it.

You're probably better off with a cheap Garmin for that. The battery will last a month instead of a day. (Or multiple months if you only wear it at night and turn it off every morning)

Sleep tracking was important for me too, but I've solved that by having whoop (it was a gift, though). It's tracking that stuff nicely, and I only have to charge it once in 1-2 weeks.

Apple watch starts at $250, Fitbit does sleep tracking too and starts at $70.