So, it seems this is a bug or issue with the Android TV Banner generation tool in Android Studio/Intellij IDEA.

Assets should be generate for mipmap-hdpi, mipmap-mdpi, mipmap-xhdpi, mipmap-xxhdpi, and mipmap-xxxhdpi, but it only generates for foreground and xhdpi. This will cause your app denied from the Google Play Store.

I used https://github.com/jellyfin/jellyfin-androidtv for an example of how this should be configured and then had to find some different image generation tools to do this manually. What a pain.