UE DEBUGGING Advice

Looking for some advice on how to Debug my standalone game. 

I have my game (UE 5.5.4) that until recently was compiling with no problems and the build was working on my headset. It recently stopped working completely and crashes as soon as the app starts on the headset. I tried migrating my project to a fresh install and same result.

I have been trying to debug the problem but struggling to work out what tool I need to use. Have tried using the Meta Dev App/Device Logs but I cannot see what exactly in the warnings is triggering the crash when the app starts. As far as I can see nothing specific to my game is flagged in the warnings.

If I run the app in UE using the Meta simulator it runs fine. If I run it via VR PREVIEW/PIE it runs fine. 

If I change the game level and instance to the standard VR template level and Game Instance - I can get the VR template level to load in headset so I know that building/compiling/Android settings are working in theory

Can anyone give me any pointers on tips/tricks/tools to debugging problems in my UE blueprints from a standalone build in headset?