I have a new 2021 6.2 RST Z71 4400 miles on it and it did the same thing to me last Saturday let it sit for 1 hour then it finally started. Took it to the dealership exactly the same codes and they had to run a new upgrade software on the ECM. Hope that fixes the problem. There is a GM service bulletin out about the problem dated February 9 or so 2021. Running a new upgraded software program on the ECM is supposed to be the fix.