Basically, what everyone else said plus this wisdom:
Do not learn Linux. Learn to understand Linux! I have never read a proper Linux tutorial in my life. My journey into Linux was based on trying to make sense of it myself, buggering up royally and learning from buggering up, "how to do X in Linux" web searches, and other peoples' guidance. This method's not for everyone, I mean the more scholarly type reads the theory, but I think diving headfirst in is best because you'll make mistakes and TBH, making mistakes is good. Mistakes teach us. I find experience is more useful a teacher than theory until you want to start studying the engineering, sysadmin, devops, etc. sides, then ye might want te study a wee bit there. Most of all, ask questions. Get an idea that you want something to work a certain way and bloody got for it. Ask people, "HTF do I do X?" and when you get answers, find out why they work.
So, my advice is dive in the deep end, and once ya can swim, then hit some books if ya get the urge. When ya do, things from experience start slotting into place.
And yes, the CLI is the best place to start. If a program runs from a terminal/terminal emulator, run it from there. By learning the CLI, it won't matter your DE or other cosmetics, so long as you have the CLI, you'll be at home.
I suggest you do a full install on a spare PC, not a VM, we want bare metal here. This is so you can safely and realistically fckup. I suggest using a less user-friendly distro. Spend a few months messing up and fixing (try to fix it yourself) and learning. My first real Linux experiences came from TinyCore, AntiX, and Debian (I was running low spec). I actually avoided *buntus altogether until much later. I still find myself a little lost in them. I prefer Mint to *buntus any day (albeit a derivative of the former). Surprisingly, more "technical" stuff is actually simpler and easier. Once you understand, that's it,because you reslise it was never so technical, that 13yo you could've done it. You'll end up gravitating to the so-called technical method, like for example the CLI, the more you use Linux just coz it's easier and more efficient than fighting with an ever-changing or unintuitive GUI. Eventually, you'll be annoyed by bells and whistles other than for unixporn.
Anyways, just thoughts, ramblings, musings. Good luck whichever path you chose (make sure it's right for you).