did you try the zoom button on remote?
could you do it on the tv itself ?
You should post what app/program you are using!!
The box settings are for the Display Resolution only (1080p/60hz, 720p etc)
Aspect ratio of videos is always adjustable in the video player settings.
If you cannot adjust, then you are using a poor application.
If it is similar to stb emu, you should be able to either select the aspect, or use an external player instead of the default player.
I recommend MX Player
what about button under 7 in remote funny they dont have that kodi you can do it in setting but that kodi and NBS would know