I only have one question that I don't see the answer for.
Have you tried jump starting it?
I've seen weak/old batteries perform the same way as described in the original post. PLUS, my '18 LTZ did the same thing when my battery took a dump after owning the truck for about 2 years. The battery was reading and testing fine, but would not start the truck (wouldn't even turn the starter). Got a jump from a friend and it started just fine. Next morning it started just fine, ran my errands, went to start it up to head home.....NO GO. AAA came out, jump started my truck, and I took it straight to the dealership, since I was still under warranty and the battery was "not old," they replaced it, and that second battery is still performing just fine, 5 years later.