Smartphone recommendation

This app is great i used to have Android and i was really happy this this app
But i immigrated to Apple ecosystem MacBook + IPhone and i’m Happy with how well this is integrated.
But there is no app like Sleep as Android for IOS
So i decide to but android just for this app
There are any diferentes how well SaA will work on low end phone ( 60 usd ) vs mid range ( 150 usd ) i will use with SaA smartwatch Garmin Fénix 3HR and some smart light ( probably philips Hue / not decided yet what to buy )