VPN impossible to delete in Ventura

Find Any File can help in removing leftover components of apps that have been deleted. Do the following:  

#1 - boot into Safe Mode according to Start up your Mac in safe mode - Apple Support. 

NOTE: Safe Mode boot can take up to 10 minutes as it's doing the following; 

• Verifies your startup disk and attempts to repair directory issues, if needed

• Loads only required kernel extensions (prevents 3rd party kernel/extensions from loading)

• Prevents Startup Items and Login Items from opening automatically

• Disables user-installed fonts 

• Deletes font caches, kernel cache, and other system cache files

#2 - download and run the shareware app Find Any File to search for any files with the application's or the developer's name in the file name.  For CleanMyMac software you'd do the following search(es): 

1 - Name contains vpn

Any files that are found can be dragged from the search results window to the Desktop or Trash bin in the Dock for deletion.

FAF can search areas that Spotlight can't like invisible folders, system folders and packages.  

#3 - reboot normally.

Bruccio wrote:

I cannot connect to internet despite full WiFi. I’ve restarted my MacBookPro several times, talked with an Apple tech expert and still cannot connect. She said she thought an old VPN network was interfering — and there is such a network (inactive) on my Mac— but I cannot delete it

For your third party —

If in doubt refer to the developers website; Support/Help/FAQ/known issues/compatibility /updates/uninstall:

Contact a third party vendor

Contact a third-party vendor - Apple Support

I see some references on line, see if it is applicable—

manually remove a profile on your macOS, follow these steps:

Go to >System Settings> Profiles.

Delete the VPN profile, and enter the user password if requested.

Then, go to >System Settings>Network ...Connections.

If you see any connections which start with or include “VPN”, delete them.

Further—

If the Button isn’t available, there is an alternative way to remove the VPN profile button isn’t available, there is an alternative way to remove the VPN profile on your macOS (see below).

In Terminal type

 networksetup -removenetworkservice “yournetworkservice”

Instead of yournetworkservice, type the name of the network service you want to remove from your macOS device, using quotation marks. If you are not sure about its correct name, you can find it in the list of your network services.

To view this list, go to Terminal copy & paste::

networksetup -listallnetworkservices

Make sure that you typed(copy & paste) the name of the network service exactly in the same way as it appears in the list.

To ensure that the network service is removed on your macOS, you can view the list of network services again:

Terminal:

networksetup -listallnetworkservices

some related reference:

How to Delete VPN from Mac | OSXDaily

Removing VPN configuration - Apple Community

Change VPN settings on Mac - Apple Support