apt install openvpn-systemd-resolved

cat /etc/openvpn/client.conf
dev tun
proto tcp
remote alexlinux.com 443
client
dhcp-option DNS 192.168.111.215
dhcp-option DNS 192.168.111.216
resolv-retry infinite
ca ca.crt
cert agorbachev.crt
key agorbachev.key
remote-cert-tls server
persist-key
persist-tun
comp-lzo
verb 3
status openvpn-status.log 1
status-version 3
#log-append openvpn-client.log
script-security 2
up /etc/openvpn/update-systemd-resolved
down /etc/openvpn/update-systemd-resolved
down-pre
dhcp-option DOMAIN-ROUTE .

/etc/resolv.conf -> ../run/systemd/resolve/stub-resolv.conf