I bought a 2010 Pathfinder in 2019,. The car has been at Carmax and the Nissan dealer for over 2 1/2 months dealing with. the computer. I have been with the car fro 3 month and made monthly payment and insurance. The car is at the dealer now.
You need a lawyer.
Not sure what dealer or carmax would have to do with 10 years old car.
If carmax provided warranty… maybe… but the dealer is definitely off the hook warranty-wise.
Other than that, @Darrell02 provided to useful information to make any recommendations.