when launching a project to a Samsung device with the Google AR Core plugin enabled on an Android device with Android Pie (9) and Google AR Core 1.8, a message box appears saying "Plugin ‘GoogleARCore’ failed to load because module ‘GoogleARCoreRendering’ could not be found. please ensure the plugin is properly installed, otherwise consider disabling the plugin for this project.
So the issue is most likely just an out of date AR Core plugin. The solution will either to wait for the next UE4.21 update or get an updated plugin from the AR Core plugin’s source build.
However any other alternative solution would be preferred.