The current VPN tools that Tasker supports is the firewall namely "Network Access". This tool is only limited to blocking and allowing apps to connect to the internet. There are a lot of features that can be added like Custom Filter by "NoRoot Firewall", a feature that can deny or allow certain IP's of a certain app for internet access. "HTTP Injector" that has a Custom DNS feature. These apps uses VPN for their features to work and I believe that the Tasker can make it too.