You might want to try using a 5w20 full synthetic to clear out the oil return holes in the pistons. That’s the cause of the oil consumption most likely. And put in a bottle of Berryman Chem tool in the oil 100 miles before changing it. That’s what a lot of people have done to reduce consumption.
Just because it’s leaking or burning oil, doesn’t mean you’re getting the crud and contamination out of your oil by attrition.
Cancel it immediately. How much did you end up walking out owing? Also, did you finance with a credit union? Reason I ask these questions, is to determine if you even need GAP, and conversely, if you did go through a CU, you can likely get GAP for $300.
You are upside down in the car and you’re going to get boned on interest because of the loan to value difference. That’s a terrible idea. If you think you can afford those payments, make them on your current car and pay it down.
I had the same thing happen with my Infiniti a couple years ago. Makes you wonder how many people fall for that.