It depends on what you want to do. The problem is that PHP is hyper-optimised for serving up HTTP. That was great in the 2000s when the web was eating the world and the other options were Java, Python, and Perl, but is less useful in the current climate where there's so many more platforms and web development requires javascript.

By learning PHP, you are effectively locking yourself into the narrow niche of backend web development (ask me how I know!), whereas other languages have much broader target platform appeal.

As an example, the obvious competitor to PHP of Javascript already beats PHP by also providing backend web services, but also has support from AWS lambda, GCP Cloud functions, and even the somewhat esoteric embedded javascript for micro-controllers options.

> Do you shoot for what has had longevity, or what's rising?

Coming back to your original question - I think it's both. Depending on what you wanted to do, I'd pick Javascript (see above), then depending on what else you wanted to do, one of Golang, Python, C#, or Kotlin.