My first “pc” was a clone of zx spectrum and all I had was a built-in BASIC and then some assembler on a cassette. Both went with “books” on how to use them, together with all of the unlimited time you have when you’re a kid.
This transferred to my first PC and eventually I learned how FAT, DOS, BIOS work, how to make a TSR and fool around B8000/A0000, first steps with 386+. It also helped that my granddad was an impulse electronics engineer and taught me how actual gates work and how computers count, sum and select numbers. He also had access to multiple books on hardware. I knew it all down to the silicon.
Other people had all sorts of magical ideas on how computers work. Special “hidden system areas”, “graphics card does X”, “computers multiply by addition”, etc etc. It’s a human thing that if we don’t understand something, our mind tries to yadda yadda it.
And the more you yadda yadda, the less chances it leaves that you’ll actually learn it. I tend to fight with these half-baked autogenerated explanations and try to dig down to how it really works. For no particular reason, that’s just what I like to do. It leaves a mark on how you work though.