>which is now busy phoning home through "Telemetry" and "Cortana" with everything you do on the machine.
All of it can be blocked. Article from 2015.
https://latesthackingnews.com/2015/09/07/how-to-block-windows-10-data-collection/
If an app can block it likely a savvy tech could on their own…powershell, god mode, or something.