It's just a neat suggestion I want to top on because destroyers just exist and it's not used because it's mostly anti submarine and almost no one uses submarines in combat anymore,
Railgun: explosion radius 12, shell shock radius 10: specialised cannon that can breach through even the toughest ships, uses copper as the electro magnetic rail material (so when the cannon the copper rails get slightly weathered it cannot be used) uses both big capacitors (or new specific cannon batteries) and 14 inch naval shell (or a new specific shell that doesn't use any gunpowder or thermite) reload time is 2 minutes for balancing purposes, just make sure the projectiles and the battery/capacitor isn't easy to craft or mass produce/nerf destroyers to have lesser speeds (projectile speed should be incredibly fast with low projectilr drop but cannon it self does not have vertical aim)