If you're interested in technical notes on how the WoW64 thing works, I dug into Wine and implemented a similar thing in my (far inferior) emulator and wrote about it here, including some links to some Wine resources: https://neugierig.org/software/blog/2023/08/x86-x64-aarch64....
FYI the link to the Rosetta branch at the end 404s. Maybe change the point to the main repo?