If You Don't Know C or Assembly, Do You Understand How Computers Work? (lakin-mohapatra.medium.com)

You need kernel assembly programming on large and modern hardware architectures (have a look at large RISC-V implementations, x86_64 has all this backward/legacy compatibility which makes simple things very complicated for no good reasons).

"C Is Not a Low-level Language. Your computer is not a fast PDP-11." (https://queue.acm.org/detail.cfm?id=3212479)