On the Raspberry pi install the dnss package
apt install dnss
Edit the settings to make it listsn on port 5053, normally it listens on 53
# Sockets for dnss.
# This lets dnss run unprivileged.
# We typically want one UDP and one TCP socket.
And restart the service, because the pi-hole is running starting probably failed right after installation, port 53 is in use
systemctl restart dnss.socket
In the Pi-hole admin web interface under settings find the tab DNS and adjust the upstream DNS Server to the dnss installation
And we're good to go. dnss uses by default dns.google.com.