They only banned ones that don't have NOx emissions controls and that are are easily replaced with portable batteries. Here is the text of the bill:

https://leginfo.legislature.ca.gov/faces/billTextClient.xhtm...

My reading suggests that this won't impact anything that you should consider plugging your house into. Instead, it's targeting stuff like this:

https://www.harborfreight.com/generators-engines/generators/...

However, that model is twice as expensive as the one harbor freight was selling before the bill passed. The old one wasn't an inverter, so the frequency / voltage would drift around when the load changed, and couldn't be used with computers (or modern appliances). It wouldn't surprise me if they slapped a catalytic converter on it while they were upgrading the electronics.

To only purchase within the state, or bring in generators purchased in another state, or to operate already-purchased generators?

Purchase within the state

You have until 01/2024 to buy one