@LeavesCat or he weakens the imperial empire such that it allows a transmigrator to take control, similar to how he took over control of a weakened empire at age 15.
But really from what we know so far, seems this is the kind of story where transmigrators are not uncommon and not that strong inherently. First the imperial empire didn't suppress his empire or develop any advantage (tech or otherwise) in the hundreds of years BEFORE he was born. Second, his main advantage as a transmigrator is that it fit so well with his circumstance of birth and bloodline.
The other four transmigrators I can recall, one of them is topping out as butler to a countess who can't even imagine beating Carmine in a magic duel, one was killed by the butler in a duel and was never gonna change the world much, one of them (OOPARTs woman's father was apparently set up to be killed by the church) and his biggest impact on the world was educating his daughter, and one of them fled the main continent to become jesus which eventually became the main religion but it didn't seem like he was a conqueror or anything.
In any case this is a world where inventing shampoo or mayonnaise isn't gonna make you a central figure.