where I can find previous backups of data (step, workouts). the last automatucal backup unfortunately does not download any previous data
In you sdcard/memory/disk is a folder amazfitnotify.
There are several files in there.
If you want to transfer to a new phone, just copy the whole map to the new phone.
Then do an Import of the backup and it should work.
I did this last week with my new phone and my wife also did this a week before.
You probably need to exit the app after the import (Exit via menu)
So in the root of the 'disk' you can find this map.