Not the solution you think it is. It would be the rural Republican areas of California that would split off, meaning the magats would have an even stronger lock on the senate.
They would be acknowledging they they won’t ever be treated as a full and independent country by doing so. They currently claim sovereignty and have special rights because of it, including the right to govern traditionally and to deny membership to their colonial oppressors
If they want statehood I’m happy to give it, but I’ve seen no indication they want it
So you would have 19 new States from splitting California, and four extra ones to fix long overdue mistakes. Flag designers will get a major headache redesigning the flag with 73 stars...
I don’t know about the California’s. I would prioritise giving statehood to the peoples who previously did not have the right to representation even though they were within US territory and citizens.