Its blue balls the manga.
Just when you thought an MC couldn't surpass to love ru in dicklessness, we bring you Keita, the ultimate "h-hey stop joking around when you touch my dick" character.
This manga would be interesting if there was actually any sort of threat involved. They had dragons and said "lul we can just blow it up" and now its about jerking off the jsdf.
Seems like your basic self insert isekai manga. MC just starts off with specialized knowledge in every field, is good at everything, and has the classic "he's competent so i love him" love interest. Meh/10