Go is a reasonably performant language that makes it pretty straightforward to write reliable, highly concurrent services that don't rely on heavy multithreading - all thanks to the goroutine model.
There really was no other reasonably popular, static, compiled language around when Google came out.
And there still barely is - the only real competitor that sits in a similar space is Java with the new virtual threads.
Languages with async/await promise something similar, but in practice are burdened with a lot of complexity (avoiding blocking in async tasks, function colouring, ...)
I'm not counting Erlang here, because it is a very different type of language...
So I'd say Go is popular despite the myriad of shortcomings, thanks to goroutines and the Google project street cred.
For ML/data: python
For backend/general purpose software: Java
The only silver bullet we know of is building on existing libraries. These are also non-accidentally the top 3 most popular languages according to any ranking worthy of consideration.
PHP's frameworks are fantastic and they hide a lot from an otherwise minefield of a language (though steadily improved over the years).
Both are decent choices if this is what you/your developers know.
But they wouldn't be my personal first choice.