So for those wondering, this was my second transaction with VROOM. First was my wife's leased Accord that was about 5 months shy of maturing, and the second was my RAM.
The newer trucks will take a few days to get an offer sometimes, but Im assuming its because they are newer and there's not much info on the current model year. Mine was a '21. Once you accept their offer, you will be prompted to enter all you contact information, loan information, payoff, etc, etc. For both of mine, I was not upside down, so this is my experience. Once you submit all the online info, you'll receive an email with some documents to sign, like POA to transfer the title. They will then FEDEX you some more documents and send a prepaid FEDEX envelope to return the Title to them. This was the only uncomfortable part. Once they receive the title, you'll get another email stating they have assigned a pick up carrier. They will contact you in 1-3 days. They will come and pick up the vehicle and provide you with a copy of their bill of lading that you will send to VROOM via email. Once they get that proof, they process your payment. In my case, the payoff check was sent to Navy Federal, and my check to me, both with FEDEX tracking numbers provided by VROOM. Both of my sales went very smoothly.
EDIT: I will add this. With my wife's ACCORD, the state of Oklahoma maintains the title on leased vehicles. So I had to go through some hoops to tell them it was a lease and I didn't have the actual title. I would then get an email saying they still need to title to process. I would call, get a rep, tell the whole story, they would say ok, and the whole process started over. Finally one day I just started the convo with "I need to speak to a supervisor". I got a very nice lady who finally helped me out and gave me her personal extension if there were any issues. After I finally got her, the process went smooth. Their offer was a great one, so I stuck with it. The RAM transaction when without hiccups since I had the title.