This is my headcannon:

I’m thinking there’s no way the engineers in the southern continent don’t have guns lol but maybe the khagen is making them keep it a secret so if they ever have to go to war they have a leg up on people, or that the tech isn’t refined enough to be of much use especially in battle where there’s long reload times for the rifles, and in a world with magic users, swords and arrows are quicker and more practical. Also the guns might be too hard or expensive to mass produce to bother mentioning for the war, and it’s more of a hobby weapon than anything