Thanks for the scanlation. Great effort but the translations feel weird. Yes they are understandable but the flow of conversations and dialogue lack a smooth flow to them.
Well I remember the guy isn't a sword or weapon enthusiast in his past life so yeah, "sad coz there aren't any katanas" is actually a reasonable reaction for the MC. If he was a practitioner of weapon using martial arts, then the transferability of using weapons wouldn't be too bad.
When in doubt, pay a blacksmith to make a Katana for you.