The getting started pages for Android show very well how to get UE4 building and packaged on the target device, but have very little advice for what to do when things go wrong. As an engine that provides/requires a custom build tool and source code, I’d expect full support for debugging on target devices.
Please post a guide with step-by-step instructions showing how to put breakpoints and step through my/your C++ code on Android and/or iOS. (And for your console development partners, those platforms as well!)