> Section 16600 of the California Business and Professions Code provides that "every contract by which anyone is restrained from engaging in a lawful profession, trade, or business of any kind is to that extent void."

That is the letter of the law, but that has not been the interpretation (re: a 2020 appellate ruling mentions this)

https://calawyers.org/business-law/california-appellate-cour...

I also happen to know that ND non-competes are enforceable in a limited fashion.