Because I’m in my very early 20s I missed out on the huge Java craze. Everything was Python when I started getting a more formal education and before then all my work was in C++. Knowing more languages would obviously look better on a CV but I mean if I would benefit in a practical sense? I have two friends who are long time Java devs. And recently another friend who generally works with legacy C++ based systems from the early 2000s late 90s period had to work on a bunch of stuff in Java. Java is clearly still in large scale use among older systems. So would it be likely that eventually I would need to work on Java systems myself when my job is mostly JavaScript currently?
The opposite actually happened to me. PHP was my first non-intern position. That company eventually started working with Java, so I made that transition when they did.
Fascinating. It has been a running joke in my bubble that no one ever picks up PHP voluntarily. It’s just everywhere.
I wouldn’t overthink it. Learn the languages you like. Learning an OOP language in depth is a good idea, but it doesn’t have to be Java. C# or even modern PHP also work fine.