Even Moses doubted in the midst of the mission.

Even while performing signs and wonders, having seen what he had seen and having experienced what he had experienced, he doubted and questioned God.

But he dealt directly with God about the matter. He did not skirt the issue or complain to others. He took the matter to YHWH Himself and this was also a part of that later reflection that he would speak to God like no other had before, face to face.

When he brought the matter to the Almighty, he was heard and he was answered. Greater glory would come by letting the process play itself out.

"Then Moses turned to the LORD and said, 'O Lord, why have you done evil to this people? Why did you ever send me? For since I came to Pharaoh to speak in your name, he has done evil to this people, and you have not delivered your people at all.'"

"But the LORD said to Moses, 'Now you shall see what I will do to Pharaoh; for with a strong hand he will send them out, and with a strong hand he will drive them out of his land.'" – (Exodus 5:22-6:1 ESV)