Sorry, I didn’t know enough about this as I don’t use such Apps and am always rooted.
It seems the setting might not be enough for very strict Apps, as they can detect (and they don’t like) even just the possibility to root.
If you put your priority on such Apps to work, the fail-safe way is switching to Fairphone OS (which is unrooted).
Else … @Roboe: Does your unroot ZIP for Fairphone Open OS still work with Android 6?
And a Google-lesser way would be switching to LineageOS for the Fairphone 2 (based on Android 7.1 currently), which is unrooted by default. It’s pretty popular here.
For reference … a wiki about excessive tinkering around … not recommended for beginners or the faint of heart 
…
Whatever you do, backup your important data first 
!