Let's focus on Arcanist first, since Arcanist is now (2023) not supported by any stable official version of PHP and this is a problem for its end-users.

A brief riepilogue:

So, let's try to concentrate directly on PHP 8.2 support since that is the current official stable.

How to install PHP 8.2 in your distribution to do tests

In Ubuntu, start with this page: https://launchpad.net/~ondrej/+archive/ubuntu/php/ in short:

sudo add-apt-repository ppa:ondrej/php
sudo apt update
sudo apt install php8.2 php8.2-cli php8.2-mbstring php8.2-iconv php8.2-mysql php8.2-curl

In Debian:

# execute the instructions from this file:
# https://packages.sury.org/php/README.txt

# then
sudo apt install php8.2 php8.2-cli php8.2-mbstring php8.2-iconv php8.2-mysql php8.2-curl

Workarounds

Use Debian GNU/Linux bullseye (current stable) that is shipped with PHP 7.3 (https://packages.debian.org/bullseye/php)

Use Ubuntu focal 20.04 LTS that is shipped with PHP 7.4 (https://packages.ubuntu.com/focal/php)

Use any other version of Ubuntu, installing another version of PHP in a safe way (https://launchpad.net/~ondrej/+archive/ubuntu/php/) - example:

sudo add-apt-repository ppa:ondrej/php
sudo apt update
sudo apt install php7.4 php7.4-cli php7.4-mbstring php7.4-iconv php7.4-mysql php7.4-curl

Use any other version of Debian, installing another version of PHP in a safe way (https://packages.sury.org/php/) example:

# execute the instructions from this file:
# https://packages.sury.org/php/README.txt

# then

sudo apt update
sudo apt install php7.4 php7.4-cli php7.4-mbstring php7.4-iconv php7.4-mysql php7.4-curl

Current situation