A 24-inch naval gun could overwhelm its own ship

Why might a battleship armed with 24-inch guns damage itself?

The shells, propellant, recoil, and structural loads would exceed what a conventionally sized ship and period metallurgy could safely absorb.

A battery of 24-inch guns would require an enormous hull and very strong structure. With 1920s or 1930s metallurgy, the blast and recoil could damage or even break a ship that could not absorb them. Real warships of the era already damaged deck planking and superstructure when firing much smaller heavy guns. Gun power cannot be separated from mount weight, hull strength, and the technology available to distribute firing loads.