First job as a web dev (promoted within my company from helpdesk!!!!). I made it explicitly clear that my php experience is rudimentary and that I was still learning and our CIO was fine with that, just said I need to fast track learning.

In my first website support meeting today they dropped all kinds of fun stuff about Wordpress development that I only know the basics on and is now my responsibility to learn, so:

How the hell do I learn php/scss/sass/docker for Wordpress really fucking fast? Lol

Unfortunately you can learn it fast, or learn it well. There’s no way you can do both.

I’d suggest just getting the basics super tight and google anything more complicated than that.

I was in a similar position 6 months ago, hired to build PHP Laravel sites with almost no knowledge of the language, I just spent a few hours each evening following tutorials and doing the basics until I knew enough to blag it! :)

Udemy(and let your boss pay for it)

If your company is willing to pay I would recommend OReilly online. there are hundreds of good videos on each of the subjects. As of order I'd start a bit with docker as it is not that much to learn and you will need it for everything later on. Then go and learn some php first. I'd lastly start with sass etc. maybe freecodecamp can help there.

PHP: you could learn it the right way, or make it work with wordpress, these are two different things, and you'll just want to jump in and follow the wordpress docs for this.

SCSS: if you already have some working knowledge of css (vanilla) then the jump up should be straight forward, just add a listener to compile on save so you can see you're changes as you go.
There's a lot of concepts to learn in here, but start simple and grow as you learn.

Wordpress: we all know how I feel about this, just expect to feel dirty and need a shower on an hourly basis depending on how the code base has been destroyed in the past.