Earlier quoted context omitted.
I'm not following. Your link appears to be specific to corporate environments. The title of the document is: "VPN overview for Apple device deployment." It further states "Secure access to private corporate networks is available in iOS ..." An individual iPhone user who is not using a company issued device would not be beholden to MDM restrictions or profiles. Nor would access to "private corporate networks" be neces…
You can create and install mobileconfig profiles on any iPhone, even unmanaged.
">Always On VPN activation requires device supervision."
Supervision denotes a managed device"
"Supervision generally denotes that the device is owned by the organization, which provides additional control over its configuration and restrictions."[1]
No regular non-corporate iOS device user is ever likely to be downloading manually distributed mobile profiles.
[1] https://support.apple.com/guide/deployment/about-device-supe...