Hi Hicham Majzoub, Apple Watch sleep data is an essential piece of the Bevel equation. The app uses several metrics from your Sleep (HR, HRV, Blood oxygen, Temperature, etc.) to tell a story about your sleep quality and recovery. Hours of sleep is simply not enough to provide you with actionable recommendations.

That said, if you change your Settings -> Customization -> Calculations -> User HRV/RHR from Entire day, you will be able to see more data from your Apple Watch, it will just be less consistent and reliable.

You can already to that in Apple Health, but you get no actual sleep data that way. Alternatively charge your watch while you shower, mine usually charges to full in 30mins