Answer
Third-party apps can be installed via any file explorer app from the Google Play Store.
Place the app you want to install on a USB stick.
Insert the stick into the TV.
Download a file explorer app (e.g. File Commander) from the Google Play Store. Make sure the app has access to all TV folders.
The USB drive directory should appear in the app. Open it and select the app to install.
If an error message appears, please go to [Settings] and allow the file manager to install files.
Select the app again and select [Install].
