That was always the balancing factor with Naval artillery.
At that shell size APHE actually becomes a effective shell type, and balancing out how much filler you put in a shell, without reducing its Armor piercing capabilities too much was a huge balancing act.
The American Super Heavy AP rounds were one of the most well balanced Shells in that regard, good filler, and REALLY good weight.
The British 14in guns were also very well balanced, the Guns on the KGV’s were capable of punching well above their weight class due to the Shells.
By WW2 Shell caliber wasn’t as important in Naval artillery.
The Alaska’s, with their 12in guns, were knocking on the doors of the Short Barrel 16in guns with Super heavy shells.
And the Scharnhorst class’s 11in guns could punch WELL above their weight class at shorter ranges.
pen is probably the most important thing next to reload bursting charges mean almost nothing
for example italian 12 inches are very good for 12 inches as they have very high pen allowing you to go through most heavily armored opponets you face and strike there citiadels
ROMA for example has most pen in the game being able to pen angled iowas and soyuz and ammo them but her long reload nerfs her hard
Americas navy is already OP we dont need anymore ships for them until they actually balance out naval
there only issue is that there dreadnoughts are mediocre cause a long reload but that’s literally the only thing bad about them
there literally the best naval tree in game already