I recommend the novel Online Campus to you. The main character, Ying Si, was an online gaming expert. His teacher had opened an online gaming campus in the other world. Ying Si was a teacher in this school, teaching the students all kinds of basic online gaming knowledge, such as positioning, damage calculation, and so on. This novel meets your needs. The protagonist is a teacher in the Otherworld. I hope you like this fairy's recommendation. Muah ~😗