My first reaction is horror that this exists, though upon reflection in actuality huge age gaps are inherent in a whole lot of isekai if you count mental age, which in a real relationship would be a big problem...
However I feel my horror is still justified—the mental age gaps in most isekai romances are sort of an accidental consequence that one presumes the author and audience are trying not to think about; here that's obviously impossible.
Still, I suppose the existence of this posits, like many works of fiction with age shenanigans, an interesting philosophical problem as to what part of an age gap would be actually ethically problematic... Luckily not something I have to answer in real life.