We're talking about a single point difference on both occasions where they pushed City to the last day.
A manager can give his team the best possible chance of winning, and then it's out of their hands.
Your logic dictates that in 2019 and 2022, Pep Guardiola was one Premier League point better than Jurgen Klopp. That's not the truth, though, is it? If you simulate those seasons 100 times each, it doesn't end in a 1 point difference in City's favor every time. It's just a logical fallacy, I'm sorry.
Very rarely will a 1 point difference have to do anything with the manager's abilities at the end of the season. Was Carlo Ancelotti better than Sir Alex Ferguson in 2010 by one point exactly? Or how do you define it? Chelsea finished 1 points ahead of us, but you surely don't think the only thing that decided that is the difference between Ferguson and Ancelotti? There's the two squads of players, small margins deciding several games, referee decisions, number of resting days between matches, I could probably list dozens of things.