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Do you have an Apple TV box? If so, which model?

Identify your Apple TV model - Apple Support

Find your Apple TV model number - Apple Support

Apps for Apple TV are available on models Apple TV HD (4th generation) or later.

Earlier models do not have an App Store.

Third party devices with the Apple TV app do not support apps for Apple TV. Third party devices would have their own app repository, as offered by the device manufacturer. Apple TV app vs. Apple TV box - Apple Community

We cannot answer that question. It is always up to the managers of third party stations/apps to make their products available on Apple devices. Contact Newsmax and ask them why. Or Google your question and see if you can find an answer there.