No matter what the non-compete says, if you're in CA, you can use your own hardware and non-work time to develop anything that doesn't directly compete with your employer/dayjob and doesn't use trade secrets/IP from the company.

Amazon though is mostly based in Washington, where no such law exists, so sweeping non-competes are legal.

The above is the reason that there is a difference between various FAANG companies. Even if the company policy requires you to get approval, if it really isn't a work-related piece of code, you can simply tell them to pound sand and CA will have your back.