Transmission Noise problems of the 2021 Kia Motor Soul

I I was on the interstate and my car started making a loud noise and decelerated. It seemed to lose power, I turned around and started home as I was very frightened. The car accelerated without pressing the gas, decelerated without pressing the brake. The tachometer was swinging around wildly. The car most of the time seemed to have no power. I was afraid of a rear end hit by another car or flyling into the back of the car in front. I was trying to limp it in to the dealer. The car only had 3400 miles on it and I had had it for 7 months. At one point I had to stop for a red light and the car would not move. I put on the warning flashers and tired to edge to the side of the street as there was a bit of slope. I turned the car off and restarted it and was able to get it to the dealer about 2 miles away with very little power. They told me it has to have a new transmission. They said they are replacing the transmission with a different kind and it will be safe not to worry, though confidence in the vehicle is diminished. I understand that the ivt transmission that kia developed in 2020 has been giving problems.