> They wouldn't need to break TLS 1.3 if they have access to root certificates, they could use them to perform MitM attacks.

It's trivially easy and almost undetectable for any nation-state to perform targeted MitM against HTTPS. It wouldn't be legally possible in most of jurisdictions, but Saudi Arabia isn't exactly "rule of law" country.

Uzbekistan tried, because they wanted zero-risk mass surveillance.

For a while Uzbekistan was trying to get retail computer stores to install a root CA on all computers sold, for convenient mitm purposes.

I wouldn't be surprised if the Saudis have access to the root signing certificates themselves. They wouldn't have to put new certificates in computers' trust stores, as computers would ship from manufacturers already trusting certificates that were signed with those root signing certificates.