I have a separate computer exclusively for VPN usage. How do I ensure internet does NOT work without VPN? (I don't want to rely on Kill Switch)

I have a computer, and every single thing over this computer has to go through VPN.

But I have other devices (phones and laptops) that shouldn’t be connected to VPN. So, not looking for a new router.

How do I ensure that the computer dedicated for VPN does NOT work without VPN?

I mean to say, I want to remove the connectivity options to internet without VPN.

I don’t want to rely on Kill Switch alone.

For now, I’m using the computer with Wi-Fi, but will soon move to Ethernet connection.

Thanks in advance!

Add one of their dns entries to the network adapter properties. That way websites won’t display unless connected