@powder-dev 

Hi,

This has already been logged as a feature request.

https://community.tp-link.com/en/home/forum/topic/615390

If you "Vote" for that request it might increase the chances that it will be implemented sometime.

@woozle 

It's great somebody requested this as a new feature. However, I looking for something more advanced I was hoping support can tell me a way to re-create something like this using access control, routing rules or firewall rules. Just want to make sure no-device can access internet if VPN is killed.

  @powder-dev 

TP-Link support should be back at work on Monday.

Apart from that, here is how I see it:

Access Control only allows to control which devices can connect to the router's network, but not whether they can access the Internet or not.

TP-Link's home routers don't allow to configure outbound firewall rules.

The TP-Link routers I own (without the VPN Client feature) don't allow me to delete or disable the routes that the router automatically generates on its own, so I can't delete or disable the route to the WAN interface. But you can check this yourself on your AX55 V1. After you've established a VPN connection you should see routes for the WAN interface and for the VPN interface in the "Routing Table" (menu Advanced  > Network > Routing).