CAN APPLE TV 3RD GENERATION BE USED with vpn router TO watch channel4 UK

The Apple TV box has no built-in support for VPN configurations, but what you set up on your router affects all internet connectivity for any device on your home network.

if it's the appletv 3g then it does not have an app store so only comes with the build in server channels

not sure if channel4 is an option there

The third generation Apple TV is still barely clinging on to life | AppleInsider

That’s not correct, routers can be configured to direct traffic to VPNs selectively by source IP.

That’s a router question - ask your router’s manufacturer. Good luck!

Probably referring to this one Apple TV 4K (3rd generation) - Technical Specifications