OP, what are you waiting for? Just tell vroom you are reporting it as stolen and then do so.
Similarly situated I would immediately mail a letter CMRRR to Vroom documenting everything that has occurred to date.
Then I would continue to make lease payments, with each payment followed by another CMRRR letter to Vroom with a simple update on the additional payment made.
You have a contractual obligation to pay the lessor, and even if you prevail with Vroom it isn’t the lessor’s problem if you end up one or more late payments reporting on your credit for the next 7 years.
Sure you can sue Vroom for damages, but is that really how you want to spend the next 18 months? And that still won’t get your credit fixed.
I fully agree on lawyering up and/or reporting it as stolen. You have fully complied with all your dues in your contract with VROOM, but they have not. They have said they cannot go thru with the contract, yet not fully reversed the transaction (returning you the car), so next step is to formally notify them thru a lawsuit and police report.
Social media, BBB.org and one of those consumer protection TV shows could help as well.