Consider Samsung Care+ as a insurance policy. If you actually dig through their website you will find out that it is handled by Alliance insurance. Similar to a car, if you are at fault you will have to pay excess otherwise it becomes a manufacturing...
I was able to successfully trade in my s21 ultra after purchasing a z fold 4. You need to continuously followup with cartlow directly and provide them with your cartlow order number
I preordered the graygreen z fold 4 and hoping Samsung will surprise me and deliver the phone before release date like whats happening in other countries