Yup. So far, that's what I've done. Got a quote for $21.8k for my car from Tesla (more on that in a bit). A local broker who I've bought vehicles from a few times now will give me $24.5k. I might still just go with Tesla because of the tax savings and less hassle.
I looked into the autotrader route but I read a fair bit on reddit that autotrader sends those inquires as leads to local dealers and it doesn't matter what the autotrader valuation is, the dealer is paying for the lead (intent of sale) and will quote you their own price. I didn't bother.
With my delivery date constantly being pushed out, I've had to submit my trade in quote 3 times now. Each time, the quote from tesla has increased in price (not by much - a few hundred each time) even though my mileage goes up a tiny bit. Guess the market for pre-owned is still really strong.