How to deal with Mutsu/Amagi weak guns?

Hello people.

I’m playing naval arcade. So I have the 410mm armed Mutsu and Amagi, which are very powerful guns with good penetration. But I notice the guns are like APCR of tanks. Very weak even if they penetrate?

The Mk 3 AP shells have very low explosive filler and therefore damage. Which means in other ships that I would’ve destroyed a shell room, only causes yellow damage.

The guns are also fewer in amount and not accurate enough to pinpoint what you want to hit.

Should I just aim at the center mass and take out bigger pieces like transmission? Also, does it get better with the MK5 AP shells?