using raspbian ( Raspberry Pi OS Lite) here.
I don't know if you have any saying in this, can only ask...
The current method of installing pihole consists of a single command, which turns up as the first result (duckduckgo). The installer does a pretty good job, apart from the occasional 'unsuported OS' topic, there are seldom any topics, that report problems AND, it's under full control of the developers.
The latest version (bullseye) has some things on board, that prevent pihole + unbound to function. The last time (first use of bullseye), I spent almost a day, figuring out why this didn't work anymore (dns loop), read here. Since then, there have been countless topics where the 'simple' solution (once you have found it) needed to be applied, this to make pihole work.
personally, whenever I deploy a new raspbian image, the first thing I do is:
# https://discourse.pi-hole.net/t/warning-bullseye-unbound/51027
# remove openresolv, install resolvconf
dpkg-query -s 'openresolv' &> /dev/null && sudo apt-get -y install resolvconf
file=/etc/unbound/unbound.conf.d/resolvconf_resolvers.conf
if [ -f "${file}" ]; then
sudo rm "${file}"
fi
sudo sed -i '/^unbound_conf/ s/./#&/' /etc/resolvconf.conf
sudo sed -i '/^dnsmasq_resolv/ s/./#&/' /etc/resolvconf.conf
edit2
a reboot is required after this, dns resolution fails after this
/edit
simple, once you found the cause...
edit
this 'unbound' configuration, preventing pihole to work, is there as you first boot a fresh deployed image, unbound isn't even installed at that time.
/edit
Do you have any impact on the decisions made for a new OS release, this to ensure raspbian doesn't prevent proper pihole + unbound functionality?