Something I've recently thought about is that, due to the increase in displacement, the new battleship may require more power.
For reference, the 1914 battleship Agincourt had a normal displacement of 27,500 long tons (and a maximum of 30,900 long tons), with a power of 40,100 horsepower and 4 propellers and a speed of 22.4 knots. And the Rivadavia battleships of 1914/15 had a normal displacement of 28,000 long tons (and a maximum of 32,000 long tons), with a power of 40,900 horsepower and 3 propellers and a speed of 22.6 knots.
This new vessel should surely have the same speed, but as it increases its size and displacement (normally around 30,000 long tons), then it would need to generate more power. What I would suggest is adding a fourth engine and a fourth propeller, to reach a power of around 50,000 horsepower and a speed greater than 22.5 knots. And also enlarge the funnels a little. For more precise numbers, Springsharp or similar calculators are required (which I don't use unfortunately).
