Apple tv Siri is not available in saudi arabia

Siri on Apple TV is a separate roll-out. It is currently supported in 16 countries, and only for the major languages of those countries.

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You would need an Apple ID account for that region, with matching billing address, and a payment method issued in that region.

It wouldn’t help you very much, as Siri Apple TV localization includes recognizing local services and their content (e.g. TV networks and apps), which wouldn’t be available in a different country.