That’s an interesting bit of information that was left out. How much equity do you have in your highlander? You can check it here:
If there is any equity, I would suggest to sell your car separately to the one paying the most and not try to trade-it in. Too many variables to work with, especially dealing with out of state trade-in.
Very few cars nowadays would fall under this. I am assuming you are looking into SUVs only. Your best bet is to go all EVs. Luckily there are a lot of brokers in SoCAL so you should have a lot of options. If you go hunting yourself, the negotiation would start a lot higher and you would need to negotiate it down and contact a lot of dealers in the process.
Ariyas (18 month lease), Ioniq5 (24 month lease), Ioniq6 (24 month lease), EV6, EV9, Solterra, bz4x, Blazer EV, Dodge Hornet, Jeep 4xe, Niro, CX-30, etc are the cars you can target (from the top of my head).
You can sign remotely and register the car, if you have an address in California. The people I know who moved to CA first got a residence, then a California driver license, and then the car.