You can disconnect from the internet or block the indeed apps when disconnected from the TikVPN server. Blocking selected apps is recommended for advanced users who are in complete control of every app running on their device. A system-wide Kill Switch is a safer option.
For Android, iOS, and macOS
Kill Switch integrates with all TikVPN iOS and macOS apps and prompts for a system-wide network lockdown
if the VPN connection is interrupted. You can also make the switch available by going to Settings -> Wireless & Networking -> More ->VPN to enable the native termination switch for Android 7 or later.