@devvv4ever thank you so much for your help and comments. I am somewhat technically competent but this is so very complicated. How will average user ever know. I think Google rigs this on purpose to make it difficult outside of their ecosystem.
Of course… They don’t want people to store data outside their servers… Data is their business We try to make it very easy for users (auto-detection of resources, integration with Android storages, etc) - but I admit that there are more difficulties of course if the sync is not 100% inside the Android software. However the manufacturers own battery saving features are the biggest step for users from our experience, and this causes the most of support time.