I learned PHP as first server-side language. PHP is known for being very flexible, you can write the same program in many different ways. This flexibility has many drawbacks, you make many mistakes that do not show up at time execution but will backbite you later.
I, as PHP program gone through a lot of trial and error. My way of designing the programs in PHP was pretty ugly and unscalable. I learned about the biography of great software developers in the PHP world and found that PHP was the first language to none of them. I was keen on learning advanced stuff like Object Oriented programming, I tried to learn object-oriented programming, It always seemed unnecessary to me unless I moved to Java for learning advanced programming stuff like OOP which I can apply in PHP.
Although I have not used Java in any of my projects, and also have limited knowledge of it, but I learned a lot of programming stuff from the teachers of Java which apply for almost any language, Java is a great programming language, There are great teachers out there who can teach you great stuff related to programming.
If you got some time, I would suggest you get some crash course in Java, and start learning the concepts of Java.
Learning in Java will make your learning a lot easier, things seem so easy to understand in Java. PHP7 came with many features such as return type, property type declaration and a lot of other stuff. while learning that stuff in PHP, it will seem unnecessary to you.
So I would suggest you to learn some lower-level language than PHP such as Java or C++ to get the real ideas behind computer programming. PHP is a very high-level language that gets compiled in C++. Things seem more of magic in It. but when learning to program in the Lower level language you learn a lot of great stuff that makes you a great programmer. Bless