I was in the exact same position -- the ecosystem looks intimidating these days, but fortunately PHP is pretty much still PHP. I started back in by getting a handle on Composer[0], which is the only new necessity, and if you have any *nix experience is just a basic package manager (so you don't have to worry about checking for updates and managing individual dependency files like the old days).

Composer also provides the benefit of a lot of neat packages that can help accomplish a lot of the heavy lifting, depending on your needs. For my purposes, the Slim Framework[1] was perfect. Beyond that, PHP still has PDO, so I wrote a simple class to manage my common CRUD activities. I haven't bought into the npm-gulp-JS-babel hamster wheel nonsense for the front-end. I still download the odd JS library and FTP upload my files.

Tying it back to the OP, I really rediscovered the joy of programming by ignoring all the over-engineered nonsense that's taken over (particularly in web dev). I stopped feeling like I'm behind if I don't spend a day learning about a process that might save me 20 minutes but will be deprecated in a month and obsolete in a year. I went back to just writing the code that does what I need it to do.

[0] https://learnxinyminutes.com/docs/php-composer/

[1] http://www.slimframework.com/