You can list multiple --remote options in the configuration file, and OpenVPN will try all of them until it gets a connection.
root@server ~
> # systemctl enable nginx.service
Created symlink /etc/systemd/system/multi-user.target.wants/nginx.service → /lib/systemd/system/nginx.service.
root@server ~
> # systemctl disable nginx.service
Removed /etc/systemd/system/multi-user.target.wants/nginx.service.