At the time it aired, there was a bit of a split between the people who thought the ending was a fresh way to acknowledge that we all know how reset-button time-loops work, and we don't need to see a denouement that everything is fine, and people who were still expecting there to be some other complication. There was even a Kinosode that spelled it out, which some of the former people feel rather contemptuously towards.
I'm definitely in the former camp. I thought it was a fresh take on time loops. The "meat" of the episode was seeing the time loops that failed and seeing them learn from their mistakes. Once we knew that the last time loop would be successful, we did not need to see it.