... if the phone proves to be defective, which this phone clearly is, you eventually are responsible when selling a defective product. ...
And therein lies the defect in your argument. It has not yet been "proven" that the device is "defective".
IF that were to occur, then you POSSIBLY would have a case for some sort of remediation. But as of now, you don't.
Good luck. I'm not how switching carriers fixes what you clearly admit is not the fault of Verizon. But good luck.