PHP syntax is not messy, I can tell you as someone who dealt with javascript (ES3/ES5/ES6 + node.js). The problem is this: the syntax of PHP is sugar. So everyone goes there, search for what they need, and then copy paste it.
However there is a whole object oriented syntax of PHP which you can learn to use. That makes things way better to manage in the long term. I have been working with js for over 10 years and I must say PHP object oriented/class syntax is not even comparibly agile to javascript, but it is still a good option. Invest time in it and you will be ok.
You cannot go very wrong with a backend language, however PHP + apache is a battle tested veteran combination, so your chance of "ruin" is minimal. That being said, if you hate it, do not use it, use something else, asking someone elses opinion is not very helpful since opinions are usually subjective and based on project.
In my case, I use PHP for only API communication, that means my client side is a ajax/fetch based SPA and PHP only returns/receives communication between databases/client, that's it.