The actual law is a bit more complicated than that. California is unusually aggressive about tax enforcement compared to the IRS and most other states, but if you're for example working for a California-based FAANG in Austin, you're probably not paying CA tax.

(This is not tax advice, I'm not a tax advisor, etc.)

No, like most states, nonresidents owe California tax on income earned from work in the state, regardless of the source, not based on the source of the income.