PSA: A RPi running Pi-hole is not a fire-and-forget item. The networked software on it, including pi-hole, sometimes has security holes discovered and exploited, and has to be kept up to date. See eg https://natedotred.wordpress.com/2020/03/28/cve-2020-8816-pi... & https://www.reddit.com/r/pihole/comments/73tvdq/cve201714491... & https://www.cvedetails.com/vulnerability-list.php?vendor_id=... (afaik Pi-hole is built on dnsmasq)