This is similar to the Network Manager section of the existing VPN doc, except its more explicit with a lot more images for guidance.
Where it differs is in relying on the VPN provider using a static IP address (many do not), and the user copying that address into the Qubes firewall UI. This is a recipe for user error and/or failed protection. The existing doc prevents leaks by blocking at the interface level and requires no hand-entered IP addresses… it is automatic.
It should be noted that modern VPN configurations protect against MITM attacks by using a certificate / public key system to verify the authenticity of the server. This is by far better than relying on a firewall rule based on an IP address that attackers can easily spoof.
Additionally, a scripted solution is often better since Network Manager has a very long history of mis-handling the import of Openvpn configs. Some details may get lost in the translation since NM VPN settings do not match Openvpn 1:1. That usually results in a non-working connection, but it also suggests that NM could create working connections that are missing important security parameters from the original ovpn/conf. If you read the original issue and discussions for the VPN doc, there was a strong tendency (from Qubes devs, IIRC) to avoid Network Manager details (guess why). There was also a requirement to keep mention of Openvpn incidental so the doc isn’t specific to one protocol; I don’t think screenshots of the NM Openvpn plugin meet that requirement. The existing script can be switched to another protocol by changing a variable.
Some VPN providers have started to supply NM connection configs directly because of the import bugs, but they are still in the minority. The scripted solutions use the VPN provider’s original Openvpn config, modifying only parameters that affect re-connection delays.
Finally, see my comments in VPN page requires rework · Issue #103 · Qubes-Community/Contents · GitHub.
IMO, Network Manager is either supported by a VPN provider, or it isn’t. If it isn’t, they will supply ovpn configs or a special connection manager. If NM is supported, they will usually supply an NM connection file and/or specific NM instructions; rarely, some may even say “here’s how to setup NM and import our ovpn config”. Why do the special GUI clients exist to the point of being ubiquitous? Because NM (and other GUIs on iOS, Android, etc) don’t capture all the necessary details. That is why its best to say “see your distro + VPN provider’s documentation for details in setting up Network Manager”. Its not like copying the ovpn and telling Openvpn to use it.
So Network Manager, though it may have improved somewhat, is not the GUI solution to the problem. If there were a general GUI solution, it would be one that replicates the “copy the ovpn and have openvpn run it”.