There could be several explanations, but one is that it’s generally accepted that about 1/3 of the Hispanics in the US are here illegally. Some illegals probably vote, but a huge majority probably don’t.
So, a significant percentage of Hispanics in the US don’t vote, which is the main reason the Dims are frothing at the mouth to pass amnesty, and the main reason any Republican is a self-destructive fool to support amnesty.
Only 22% of voters in Texas are hispanic. So many are illegal, guest workers or under 18. It would still be decades before the state turns blue.
The GOP get 80% of the white vote in Texas and only around 50% of the white vote in California. That is a bigger difference.