I asked Sir Chat GPT and they gave me following answer:
"Warship turrets typically use 2 or 3 guns rather than 4 for a few reasons:

Weight and Space Constraints: Adding more guns to a turret would increase its weight and size, making it more difficult to mount on a ship. Turrets with 2 or 3 guns are typically the largest that can be accommodated on most warships while still maintaining a reasonable balance and maneuverability.
Crew Efficiency: A gun turret with too many guns would require more crew members to operate, which could become a burden on the ship's resources and limit the number of available personnel for other essential tasks.
Technical Considerations: Turrets with more guns may require more complex machinery to operate, such as the gearing systems that allow the guns to be aimed and fired. Additionally, a turret with four guns might have difficulty distributing the recoil force of each shot, leading to instability or damage to the turret.
Overall, a turret with 2 or 3 guns offers a good balance between firepower, weight, crew efficiency, and technical feasibility for most warships. However, there are some exceptions, such as larger battleships, that can mount turrets with more guns, such as the Yamato-class battleships of the Imperial Japanese Navy during World War II, which had turrets with three 18.1-inch guns."

So allowing ONLY Heavy Turret to carry 4x 14-inch turret makes sense.

there are 4 cannon turrets irl..

but only in super battleships (if this class gets added to the game) because most of cruisers would sink themselves if they had

not really there's the king george v, dunkirque richileau, and other fairly numerous plans for quad turrets to be used on battleships if not for treaties and resource drainages. the most compelling reason to not use quad turrets or even triple turrets for that matter was gun dispersion, a well place hit on one turret could disable way too many guns at once.

yep

like richelieu class battleship