The short answer to your question is no. Samsung Health can be set up to track the number of hours you sleep but will require a manual confirmation to record that data. This data goes by the amount of time your device has been in sleep mode at night (I suspect when the device is in sleep mode longer than 3 or 4 hours without being moved or screen activated it knows to start recording elapsed time for sleep)
With regards to your watch and tracking the quality and time of your sleep, my understanding is that there is no alarm but rather the detailed information of the different stages of sleep you were in (Light, Deep, REM).
This might not be what you are looking for but this is a start to tracking the target time you are looking for to help you get into a healthy habit of sleeping and waking up at your target times. Hope that helps. Happy Sleeping 😴
