After learning HTML, CSS and Javascript, PHP is a good next choice on the path to self-learning web development in 2024. The whole idea is to achieve "world is your oyster" with the minimal number of steps. Don't agree? That's fine. Web development isn't meant to be dictated to others.
Elixir looks great. It reminds me of the functional and pseudofunctional programming languages I used at uni and their environments like Poplog.
I agree it's mind-expanding.
But I don't think most web development work is mind-expanding or a realistic application for it.
I also don't think using it to criticise PHP is really the right target. If you want to use a functional programming language/environment as a critique of modern web development... maybe start by targeting server-side JS.