Yeah its free on mobile but it doesn't work, at least for androids it doesn't.
The iOS version works for me
I have a Redmi Note 9S, my friend have a Samsung Galaxy A70, we also use Bluestacks and the game works fine on each device. It is maybe a problem of your Android? What device(s) do you have?
HTC Desire 530
Might be a problem of the device but idk, for me worked
