MTL - Heartwarming Kiss - Chapter 3 dispute

An accident gave Ye Han a magical ability to see through. Since then, his life has become rich and colorful. He has developed the strongest business empire, dominated the gambling world, and rejuvenated his medical skills. He has become a master of medicine and Taoism. The goddesses rushed towards him one after another. As a man, and a limited edition man, Ye Han was under a lot of pressure and had to go on an exploration with a few tomb robbers. However, a shocking secret from ancient times to the present gradually emerged. in front of him!

- Description from novelbuddy

He became a teacher at the best magic academy in the empire.
….For being mistaken for someone else.

The protagonist, having degenerated into a “loser” after being unable to find employment, gets caught up in someone else’s attempt to commit suicide-by-train and ends up traveling to another world. The numerous cheat powers he demands from God are all granted to him. But contrary to expectations, these powers bring about disastrous consequences for the protagonist.

Having reincarnated into another world, the optimistic protagonist (Yuuri) starts his(her) heart-warming training days with his(her) teacher.

She had a dream: the world was brimming with light. Family. School. Friends. Trains. Buses. Movies. Books. In that world of light, she grew into adulthood… and at the very end, in a white room, she fell into darkness. She awoke from the dream to find that she had become a demon. In the demon world, she lived a carefree life until she encountered a powerful being.