EDIT: After doing some further digging, I found the solution to it.
Solution: Package the game without using Launch, and manually install .ipa to iPhone through iTunes
Source: iOS Game Black screen? - Mobile - Epic Developer Community Forums
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Does Unreal 4.8 only work with wildcard for app to run properly on iphone after packaging them?
I created an empty project with mobile as default setting (which gives the 2 touch controls). After packaging them and running them on my iPhone, it gets stuck on the splash screen. I am currently using explicit ID because I plan to have in-app purchases.