If you want some modern day fun with this, try the Zachtronics programming games; TIS-100, Shenzhen I/O, and Exapunks.
Or, my personal favorite I only discovered somewhat recently, try Turing Complete. You start by designing all your logic gates from just a negate gate IIRC. You eventually build up an ALU and everything else you need and then create your own computer. Then you define your own assembly language and have to write programs in your assembly language that run on the computer you've designed to complete different tasks. It's a highly underrated game, although it takes a certain type of person to enjoy.
Another interesting low-level interpreter/emulated system to look into for anyone else trying to get started with this type of thing is the CHIP-8! It's a pretty basic 8/16-bit instruction set (there are 35 opcodes, the instructions themselves are mostly simple) and there are tons of detailed guides on making one and writing roms for them.
When I was young, we didn't have hex codes, we only had 1 and 0s. One time we where all out of 1s, and I had to code a whole Database system with only 0s!
I would argue they don't know what that means really. Assembly is pretty much a mapping of words to machine code. It's just a way to make machine code easier to read. It doesn't actually change how it works.
A compiler re-arranges and modifies things so what you write isn't the same as the final program that is created. With assembly it is. It's not really an abstraction, but a translation. It doesn't move you further from the machine, it only makes it so you're speaking the same language.
When I learnt programming (back in early 2000s) the textbook said C is a high level 3rd generation language with 4th gen languages being something higher (I don't remember what examples were given specifically). This is back when the java applets and action script for flash were the hot things. How I miss the days without the world being cursed by JS.
When the gp's book says that C is a third generation language: I would guess the first generation is Fortran and the second generation contains ALGOL and BCPL. C was heavily influenced by BCPL. (get it? C comes after B)
I mean, C is a high level language? Now, sure, C isn't a super expressive language and every C statement compiles to very few assembly instructions comparatively speaking, but it has a whole lot of stuff that assembly doesn't have. Like nice loops and other control structures and such, and not worry about which processor registers are used.
In the modern world it's completely subjective.
The lowest-level language is probably ASM/machine code, as many people at least edit that regularly, and the highest-level would be LLMs. They are the shittiest way to program, yes, but technically you just enter instructions and the LLM outputs eg. Python, which is then compiled to bytecode and run. Similar to how eg. Java works. And that's the subjective part; many people (me included) don't use LLMs as the only way to program, or only use them for convenience and some help, therefore the highest level language is probably either some drag-and-drop UI stuff (like scratch), or Python/JS. And the lowest level is either C/C++ (because "no one uses ASM anyway"), or straight up machine code.