For those interested in writing a debugger:
There are a series of tutorials on how to write a debugger from scratch
for Windows x86-64 using Rust [1].
Additionally, there is a book titled "Building a Debugger - Write a Native x64 Debugger From Scratch" by Sy Brand [2].
I prefer RISCV as an starting assembly language because: it has good design, it's more intuitive, it has modern language and tool support (GCC, LLVM, Rust, etc.), and it runs on QEMU and real available hardware.