I have Pihole running on a Rocky Linux 8 which was built using the normal Pihole script.

When running the script, I get:

curl -sSL https://github.com/pucherot/Pi.Alert/raw/main/install/pialert_install.sh | bash

############################################################
Pi.Alert Installation
############################################################
Thu May 18 14:51:32 EDT 2023
Logfile: pialert_install_2023-05-18_14-51.log

Installing dependencies...
sudo: apt-get: command not found
sudo: apt-get: command not found
Pi-hole
Checking if 'pi.alert' is configured in Local DNS...
Adding 'pi.alert' to Local DNS...
Lighttpd & PHP
Installing apt-utils...
sudo: apt-get: command not found
Rocky linux uses dnf instead of apt/apt-get... I recommend a script to detect the linux version. BTW -- all the required apps are already installed. The script should detect them just like the Menu app that ran correctly. :)