Can't install Pihole after OS Reinstallion

[deHakkelaar]

I think best is to start with a fresh Pi-OS lite image.
OOTB without Pi-hole installed or any changes made, below one should resolve to an IP address first:

$ dig +short install.pi-hole.net
aws-ls-lon1.pi-hole.net.
18.169.210.144

If not, you have networking issues that are not related to Pi-hole.

@nprampage

According to Change DNS servers - Raspberry Pi Forums, you should edit your /etc/dchpcd.config to assign static servers.

Above only applies for pre Pi-OS Bookworm releases.
Bookworm and above use NetworkManager instead of dhcpcd which can be configured with below (Network Manager Text User Interface):

sudo nmtui

EDIT: Some hints about prepping a Pi:

Prepping a Raspberry Pi 1B for Pi-hole with Raspbian 12 Bookworm

I noticed some users asking for more detailed instructions for installing Pi-hole on a Raspberry Pi or another Linux setup. As I was in the process of reinstalling both my trusty Pi 1B's with Raspbian Bookworm and the latest Pi-hole v6 release, and usually I document the steps, I thought why not share here. Both Pi's have served Pi-hole reliable for over eight years now, still running on the original SD cards, and I think they have many years to come. As its a headless setup, I'll be doing so…