The VG Resource

This game is available on iOS and Android, and I tried going through the assets of the Android APK. However, all I found was the splash screen, game icon, and generic GUI elements.

This leads me to believe that the game's assets are downloaded from a server, so I would need to access the game's cache or persistent files, which requires rooting. It's nearly impossible to root a Samsung device in the US, however.

My last resort would be using an Android emulator to get into those files for any chance of ripping them. Could anyone assist me or give me advice with getting assets such as character portraits, general UI elements, models, sounds, and voice lines? Thanks in advance.

I think you should try to do the Android emulator "play" in order to download those files if possible. I am interesting in them too.
Most of mobile games download the data from the server, so it is necessary to download 'the resources' first before downloading.
Also I would export the apk of the 'downloaded game' to your pc.
Do you know by any chance if the game is made with Unity?