I spent a few years trying to work on legacy PHP systems. Would never take another job using it if I had any choice. Most large tech companies do not have large PHP codebases, and most small ad hoc PHP codebases are awful to work with (in my experience), so the intersection of "uses PHP" and "higher quality software engineering" is pretty small. I won't say it's an empty set, but it's a small opportunity space. Meanwhile, the odds of having to work on really awful codebases are... high.

Generally - we live in a world with lots of fantastic programming languages, so I would never choose PHP for a greenfield project if I had a choice, and I would not pursue professional opportunities with legacy PHP codebases except in very special circumstances.