Transmission Not Go Into Gear problems of the 2017 Kia Motor Sedona

The van started to make a rattling noise from under the hood 09/30/2020. The check engine light came on the next day 10/01/2020. I called the dealership they said they didn't have available time slots and it was first come, first serve. Then the van seemed to be slipping(not catching gears) 10/04/2020. That evening 10/04/2020 as I was driving home on the highway 70mph the van shut off (as I was driving) I managed to try and steer the van to the side of the road. I tried to restart the van, but nothing(not even my flashers were working. I sat for 10 mins then tried again to start the van. It worked, however there was now a worse noise coming from under the hood. I was able to drive another 3 miles before it shut off again, mid motion 58 mph. Again I waited, after 23 mins I was able to start the van and try to get closer to the dealership. This is when the van blew up!!!! as I was driving again, shut off mid motion. This time however, there was smoke coming from the hood. I called a tow truck and our van is currently at the dealership where they are stating we've never done maintenance to our van. We have proof of oil changes from July 2020 and January 2020, September of 2019 and January of 2019. They are saying the motor need to be completely redone and that were not covered under the 100,000 power train warranty. Our van only has 68,000 something miles and it's a leased vehicle.