Thank you for using Apple Support Communities! I see you have a question as to why Bedtime in the Clock app does not track time asleep. This is normal to see as it will only track In Bed time.
If you would like to track Asleep time, that can be done using a sleep tracker with the Health app. Learn more here:
Use Bedtime to track your sleep on your iPhone - Apple Support
Specifically, take a look at this section:
How to view your history in the Health app
Open the Health app, tap the Health Data tab, then tap Sleep > Sleep Analysis. Your Sleep Analysis shows the amount of time that you spend in bed or asleep.
Bedtime in the Clock app tracks time that you spent in bed, but not how much you slept or moved. Your Apple Watch also doesn't track sleep or time in bed.
To track how much time you sleep, try using a sleep tracker with the Health app. You can also manually enter how much time you slept. Learn how to add data or devices to the Health app.
Cheers!