> If you want to use packages then you'll need to use a Package manager, you still need command line experience etc.

PHP has a package manager IF you want to use the vast offering of open source PHP libraries and frameworks.

https://getcomposer.org/download

To use it, create a composer.json and run:

  php composer.phar install

On my systems, I like to alias it so that I just have to type:

  composer install

Alternatively, if you use a Jetbrains IDE (i.e. PHPStorm), you can usually install dependencies with one click.

> And to be fair, as a naive non-PHP user, I have 0 clue how you would go about setting up long running scripts that don't necessarily correlate to a web request.

php /path/to/script.php

It can run as long as you'd like.

If you want to do it on demand (i.e. writing a webserver in PHP), that's difficult. But generally: Why would you want to do that? It becomes an X-Y Problem.