Is there a way to build an app with ExpBuilder, that has some more editing functionality than the basic editor widget?
What type of editing functionality were you looking for?
Configuring editing settings and creating a Form is your starting point:
Adding the functions which are currently available and working well in WAB would be a start - including cut, union, reshape and undo/redo. These are critical for our current workflows and we will not be moving to EB without this functionality being available.