> Do you understand how your code gets translated down to C, assembly, machine code?

yes, actually, and thats why i can debug and fix shit most people cant (and why i get paid what i get paid)

  > How all that becomes electrical signals on a PCB? How the material properties work at the physical level and how its manufactured? 

this is a non-sequitur imo, but you should def be aware of material properties and limitations (for example cpu throttling and bottlenecks caused by manufacturing process/cpu bandwidth or battery limitations help inform what is going on at a high level many times)

  > "If I have seen further than others, it is only because I was standing on the shoulders of giants," Isaac Newton

by standing, he means understanding and building upon what others discovered