If you like Photography, I strongly suggest to try app: TelloFPV.
There is a Demo version, that allows you to verify if it is compatible with your phone and controller. It is free.
So if it is ok, then you can purchase the full version for less than 5 Euro.
It is FANTASTIC!
It has very good Auto Pilot functions and also Fine Tuning of your joystics (screen ones or Controller)
An the developer is more than responsive!
Xiaomi Mi 2 repeater to extend control distances and reduce video lags/errors.
External USB/OTG controller (test it with TelloFPV Demo version)