I made a separate post about this issue and documented my progress towards finding the solution, that’s here: Packaged .exe does nothing (silent crashes) - Development / Programming & Scripting - Epic Developer Community Forums
TL;DR: Debug the executable that’s within your YourBuildDirectory/Windows/YourProject/Binaries/Win64/ directory - in my case that actually gave callstacks that helped me locate the problem code, whereas everything else I tried was a dead end.