Project specifically not working on my new phone

If the editor sees the device for launching on then the ADB driver is installed. From what you said about seeing the splash screen it sounds like it installed and ran, but hit an error during startup. You need to look at the logcat to see why it failed. Either run monitor, or type “adb logcat -s UE4 debug DEBUG” in a command window to see the log from the device filtered to the UE4 and system debug tags.