Herohero
Personally he gain a lot, mainy because he can now create more devil fruits with this tech, fruits that he will take time and resources to create, whats more important is that he is now closer to create a multiverse portal and go other places like the owl house, hazbin hotel maye even star vs the evil forces, who knows, travel to the future its to dangeorus for me, he is already in a play with bills, just when he has bills powers he could travel time without consequences, if mc want op tech then simply travel other universes with op tech that doesnt have broken cosmic entitys
He could create a devil fruit that essentially let's him get infinite powers from devil fruits. After having studied time and space he could create two devil fruits to control and create time and space energy or something and he can use them both to travel the multiverse by using his energy to create portals without a gun.