The Greatest Beast Trainer: Building a Nation on the Back of a Dragon

Solomon transmigrates to an apocalyptic world that is completely barren. The rain is acidic and dust fills the sky. A mutated bunny-eared lolita saves him when he first arrives and also ties a training and cultivation system to him.

He trains up a young dragon and keeps evolving it to become a giant dragon. Its back is thousands of miles wide and can contain fertile soil and grow all sorts of fruits and vegetables, so he ends up turning it into his home.
He cultivates a flower and it soon evolves to become a world tree that can protect the world from poisonous winds and rains, cleans up pollution, and causes blue skies to reappear.
He trains up a huge army of bats, and nobody will dare to provoke him. Everywhere that this army goes leaves a trail of death behind.
He keeps a little bunny-eared lolita, hugs her, fondles her, pushes her onto the bed and we all know what happens next.

In a matter of years, Solomon becomes the king of the world.