So I have noticed that despite military cities having guns, they never use them. It makes no sense. So, I propose two options

1. You can send soldiers to cities to attack them. They would just shoot the buildings and other soldiers.

2. Soldiers could go on the walls and act as a cheaper weaker version of turrets or just stay on the ground and shoot enemies there.

I hope you agree reader that this is an interesting idea. And now, I bid you adieu!