2020 I30 N-Line Sedan transmission blown at 65km?

So I bought a second hand 2020 I30 N-Line Premium Sedan from a dealership with one previous owner, good condition and 65 000 kms last week and first drove the car on Monday. Less than 5 days in (yesterday) whilst driving on the highway in sports mode I noticed the car was starting to rev whilst I was trying to maintain speed. I check the speed/revs and I’m dropping from 100, 95, 90 whilst I’m trying to put my foot down to speed up and it go to the point where it was almost red lining and no acceleration. Pulled over and turned the car off and on, tried to accelerate in drive it would just roll and rev, tried reverse same thing, tried flicking it into 2nd gear (DCT) didn’t work. Had to get the car towed and now going through the dealerships warranty process. The issue is the car was genuinely good condition, had a mechanical inspection in May I believe and only 65 000kms. I understand it’s a DCT but the transmission shouldn’t be having a major failure this early in its life. I’m curious as to what part of the transmission is failing and how it happened.