Look at this mess.
https://apps.npr.org/primary-election-results-2026/states/CA.html
The problem with "top two" is it means the winners are selected by minorities in the 20% range. You could get two Democrats—in which case why not just hold a D primary?—Or two Republicans, if five Ds run and 3 Rs, and it splits just a little uglier than it did in the example above. Imagine if Toni Atkins had run, imagine if the vote between Hilton and Bianco had been a little more even. Republicans coulda owned the general ballot with 40% of the vote.