2023 - Transmission Issues

I have a 2023 Sorrento that started having a loud noise around 65,000 km. The dealership finally got approval to replace the transmission in May of this year. I’d like to know if anyone else in Canada has dealt with this kind of issue. The transmission that they put in was rebuilt. The dealership told me “there is no such thing as a new transmission”. Also, the warranty on the new transmission is only 20,000 KM. At about 17,000 km after having the replacement done, I noticed fluid leaking on my driveway which turns out to be transmission fluid, requiring another replacement. I’ve contacted Kia Canada, they tell me to only deal with the dealership. The dealership tells me that those are the rules Kia Canada set. When looking up the part on the Kia website, it states that the warranty is minimum of one year. Does anyone have any insight into what the real warranty is? I put a lot of kilometres on my vehicle, and I’m very concerned that this next one will fail after the 20,000 km.