The issue with the Phantom RTK and iOS has always been that it requires the use of the SDK remote which doesn't support the recording of the OBS files people use for PPK processing.
The aircraft supports waypoint flight just fine and has been supported with Map Pilot Pro for a while.
The new iOS update added the ability to specify an NTRIP server which had been widely requested for users not using the DJI groundstation.
We are just now starting the work for adding RTK support in the Android version. It will not currently connect.
The Android version does have DroneLogbook support which should work fine once installed on the DJI remote.