Vehicle total loss - can I appeal it?

I got into a car accident about two weeks ago with my newly financed car that cost me around 41k with taxes and delivery fees. I live in California. My car insurance did not complete a full inspection or a vehicle teardown and claimed that the cost of repairs would be $25,500 deeming it a total loss (because it’s over the 70% threshold) from their INACCURATE valuation of my vehicle ($30k and some change). I am now negotiating my ACV with them to bump it up to at least $41k-$42k. Since a teardown was not done by them (they said it’s a total loss off photos and a 5 min walk around), I got it done by my mechanic who said that there was no frame damage, no structural issues, and no damage to my engine either. Airbags also did not deploy plus the car still runs fine. Once they give me my negotiated ACV, would it be possible to appeal their total loss decision if it falls under the 70% threshold? I’m going crazy trying to work with my insurance but they’re cornering me to total the car so that they can profit off of it with an auction. Please help me out with any advice or info!