...and the username just made the meme, not the art.

Also

a) low resolution image

b) the collar looks wrong, megumin wears no bell, and what is that buckle? looks like garbage.

c) the holes on the chair are not parallel, the one on the right makes no sense

d) what is that green thing on the right? most weirdly shaped pillow ever?

My assessment is: AI indeed, but check the one on Instagram (it's a bit higher quality) and you decide.