Alas, the text of the proposition is what it is.
TRUMP "MISSED THE DEADLINE" TO CALL OFF TX GERRYMANDERING; CALIFORNIA WILL NOW DRAW NEW, MORE “BEAUTIFUL MAPS”
Actually, no. That was just a childish social media post by Newsom in response to similar, childish social media posts by Trump.
The text of the proposition states:
First—This measure shall be known, and may be cited, as the “Election Rigging Response Act.”
...
(n) It is the intent of the people that California’s temporary maps be designed to neutralize the partisan gerrymandering being threatened by Republican-led states without eroding fair representation for all communities.
Literally everything about this proposition was ostensibly in "response" to what Republicans were doing, right down to the title of the act. So it would follow that if it is found that Texas may not gerrymander their maps to benefit Republicans, the "response" to "neutralize" is no longer needed, because as the proposition also declares:
(i) California has long stood as a national leader for fair, independent, and nonpartisan redistricting
Therefore, one would expect that California would be quite pleased to be able to use the "fair, independent, and nonpartisan" maps that they claim to love so much if Texas' gerrymandering is disallowed.
Of course, you have to believe that Democrats actually
want "fair, independent, and nonpartisan" maps to believe that's true. And that's why I said it will be interesting to see if Texas is not permitted to use their gerrymandered maps how California will "respond". If Texas is not permitted to use their gerrymandered maps, Democrats lose the weak cover of "Well, we really don't want to do this, but we HAVE to."