I'm looking for an alternative to "sleep as android" as its not FOSS.
What I would like is the customising that "sleep as android" offers:
-alarm that rings at a specific time during weekdays, and another time during weekends
-alarm sound that gradually increases volume
-alarm chooses from a selection of songs, with shuffle.
Key Sleep as Android feature is a smart alarm which uses sensors (on phone or wearable) to determine when you are in a light sleep phase and will wake up more easily.