You're using logic for an anime and manga. After three years of training Saitama punches out some of the most powerful beings with supernatural and godly power and break reality.
And in this one the goddess gave them a holy item that the sage tries to analyze while he trained for millions of years in a couple of seconds from the Sage's pov. And this is the first chapter with no idea what he has been doing since he has been drawing on the tree with it.
And I have seen characters who learn to cut space and concepts with basic training with less training.