I have a 2021 CT5 in which the mechanism to open the door on the handle broke - different cause but same problem. You are making the same mistake that I did - it is actually a 2 stage unlock process with the key. You have to turn the key down clockwise twice in order for it to release from the second catch. The lock actually shows this process - It shows a #1 with a curved arrow pointing clockwise and a #2 with a curved arrow pointing clockwise. The part is on back order so the dealer showed me how to properly do this in the interim.
