Hello flyboys & flygals
After having overcome my frustration of not being able to stream from my drone (and having contacted DJI to no avail) I was able to stream succesfuly by downgrading the DJI Go 4 app  to 4.3.16 which you can download here.

I'm also experimenting with  ZLMediaKit, a media server running on Android which accepts RTMP and can deliver streaming in RTMP(S), RTSP(S), HLS and MP4 not to mention adjust the video quality and bitrate (alas the project is in Chinese). Here's my apk, you can find the settings in /storage/emulated/0/zlmediakit.ini . For RTMPS, RTSPS and HLS over HTTPS you need to generate a private key at /storage/emulated/0/zlmediakit.pem

Happy streaming

For some reason the links were removed, the apk is in https://filebin.net/7ebqanew6p2a5pnt, ypu can Google the rest