YOOOOOO. THE ARTIST FOR CHOUJIN GAKUEN!! HELLA READING THIS.
Also this is actually pretty dope. Give credit to the artist for strong image conveyance of spells. It would've otherwised not look so badass, honestly.
The author wrote an entertaining "Cheat" character, and that's the most important part of creating a character who has stupid amounts of power. Self-inserts are bland and boring by intentional design. The more average and bog standard they are, the more "relatable" they become. This however, makes it really easy to. well. Define them as bland and boring Mary Sue's, who do nothing but win.
This protagonist has. GASP. Personality! While it's still surface level, it's definitely better than the aforementioned "average joe."