VPN Killswitch and keep-connection-alive toggles or scripts

[rherr <rherr protonmail com>]

I have Alpine Linux with the OpenVPN plugin. This works very well importing and automatically installing my .ovpn file. I like the settings menus and this makes the setup very easy. I haven't found a VPN killswitch or always on (persistent) connection feature anywhere. I  also have nftables on my system. I read that nftables is the new standard for Linux. I have done a killswitch and always on feature using mods to a file (using "nano") and with "ufw" (firewall) on an Ubuntu system before nftables became the standard.

I am comfortable with working in the terminal and making mods to files. I don't know anything about nftables. Is there a way to get the features onto my system? Thanks for any advice.