Hi, I am a new mini 2 owner, I have taken some video which looks great on the app and a full length but when I cut it down from say 1.00 to 20 secs the playback becomes jittery..just using auto settings on drone and photos on iPad Pro to edit/trim clips...any tips

Try using iMovie on the iPad.  

Thanks.. I did think of that but wasn’t sure it would work..seem like photos os allows to basic cutting but then ruins the quality

Still not great on iMovie

Do you have a desktop? You can do lossless cutting with avidemux.

AviDemux:
http://avidemux.sourceforge.net/download.html

Here's  a really nice tutorial about lossless cutting:
https://help.presentations2go.eu/editing/CutwithAvidemux.html

Are you increasing the speed of the video itself? If so, there is only so much % you can slow/speed up your footage without it becoming jittery.