To update the DNS resolver, be sure to include the following in your OpenVPN config:
script-security 2
setenv PATH /usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin
up /etc/openvpn/scripts/update-systemd-resolved
down /etc/openvpn/scripts/update-systemd-resolved
down-pre
Overview
openvpn
packageopenvpn-update-systemd-resolved
package (AUR)