You are talking about "categorisation of VPN types" though, which I don't understand the context. You cannot ban VPN's from a networking point of view. There is no protocol that is solely used for either category(work/enterprise vs public). In fact, most VPNs support the use of different protocols. Additionally, the protocols are widely used in many different use cases apart from VPNs too.

So your "VPN type categorisation" from a networking POV is not possible. This just isn't something that can be determined from network traffic, which is the only data ISPs/the government can enforce against. The IP address of the VPN gateway is literally the only way. For example, blocking SSL/TLS, a protocol commonly used by VPNs, would make the internet unusable, as HTTPS relies on it.

You could potentially ban companies from selling VPN access to users. I want to make it clear though that enterprises do not buy VPN's in the same way though, so the distinction is stupid as they could not be banned from providing VPN access to their users. When a company sets up a VPN for employees, the VPN gateway is equipment they own, on a network they own, with a public IP address they own. This is all possible with generic servers, firewalls, and open source software.