I recently got the Watch Pro 2. It tracks my nightly sleep rather well, however, it doesn’t track my daytime sleep for some reason. I slept from 8 p.m. to 2 a.m. yesterday, which it tracked accurately but failed to record my afternoon nap from 2 to 4 pm yesterday or my 7 am to 11 am sleep today.
Suggestion: If it is difficult for the watch to monitor sleep twice a day, there may be a button in the sleep app on the watch that allows us to manually indicate that we are going to bed.