Could you expand on that? In which fields would you work with these skills to earn good money?

Will add more in a bit, but mainly data scientist in Big Tech and Finance. At the right firms/teams your salary will grow much faster than linear in time

Doable without a degree? Any god resources or pointers?

Thanks in advance

Same here!

Unless you can leverage special instructions / hw to realize your array operations, loops will be the fundamental operations generated by the compiler executed by the CPU. For a lot of scenarios, loopless code is surely more expressive. However, I would not say that it is per se in any kind superior. Rather, it is a feature of each language, how much to abstract from the actual CPU instructions.

So to have fine granular control over your generated code, classic loops in C always relevant, while a simple array operation can be expressed in such high level way for other use cases.

I like C for the small set of basic rules and that it does not impose much cognitive overhead of learning too many new things for a given project I have to get to know. Typedefs were already too much and I prefer not to use them...

Typedefs are nice if you do not want to write 'struct' all the time...

Yes! Typedefs are definitely worth the time spent learning them.