with proxmox and ubuntu vms you can use this. PIA gives you ovpn files. you would have to create a file with your username and password and add the line into the conf with the location of where you saved it. There are two settings to make it reconnect. one is the service manager, systemd in ubuntu, to keep restarting the service if it stops. the second is in openvpn conf to make it reconnect. you can also enforce the rules you created on your router. so no packets ever go to the CIDR ranges that should be going into the vpn. while the vpn is down it may try to do this.
https://docs.ubuntu.com/core/en/stacks/network/easy-openvpn/docs/openvpn-client-setup
I'm not sure what all easy-openvpn makes easier than the openvpn package that is just as easy to install from the repo. dealing with snaps can be a pain so try the regular openvpn package if you can't get the snap to work for you.
I would recommend starting with finding the CIDR ranges you need and checking the ip of the vpn servers. if the vpn server ip is inside one of the CIDR ranges it will be a lot more complicated to connect.