We’ve had mixed experiences with Carmax. We took an Outback there and got an offer that was comically low. When they presented it and asked what we thought I told them it was too low and showed them KBB/Edmunds. The person helping us was surprised that they were that far off. We sold it private party for several thousand more.
Took my wife’s Lexus there a few months later and they gave us a competitive offer and we sold them the car on the spot.