Here's a bulletpoint version with a few additions of my own.
Size
*No harbours in the world could handle that ship back then. Indeed, no harbour could handle it today.
*Since you're using roughly 1920-1930ies technology this ship will be riveted together. The Iowa class is as far as I'm aware the longest riveted ship ever built and it practically marks the limit of how far you can go with rivets. Currently your ship is 421.4m long oa. Even if we stretch the limits of the technology you'll still have to cut off at least 100m.
I did a very quick axe job to see how that would look
*Why is it so big? A ship this size confers no meaningful advantage over more conventional battleships.
Artillery
*Why do you want to mount 12 main guns? (I can't remember their bore) They don't confer any meaningful advantage compared to the cost (design-wise) of installing them.
*Why do you insist on using double tier casemates? In the hull no less! Casemates cannot elevate anywhere near as much as deck or turret mounted guns. This obviously impacts their AA performance severely and, more importantly in this scenario, their range is limited.
When mounted in the hull they also weaken the ships structure and in heavy weather they tend to get flooded which makes it impossible to use them.
Double tiered casemates are also very hard to supply with ammunition because traditional hoists cannot be used.
*AA. While it's true Airships doesn't provide much of a threat they due pose
a threat. Currently you have no way of dealing with it.
Misc
*Boat stowage. You have oceans of space on your ship, so why do you make those indentations in the hull? They serve no purpose and will weaken the structure significantly. You also doesn't have anywhere enough boats.
*Funnels. They need to be much taller
*Masts. You don't have any. You need them for look-outs, signalling, radios, spotting etc.
*Directors. The ones you have now are much too small and they can't turn. You also don't have any for the secondary guns.
*Anchor stowage. You don't appear to have any. At least, you've put port-holes where the chainlocker should be.
*Bridge. It'll need to be much bigger. You could easily add two or three decks and extend it all the way back to the (Heightened) funnel
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