A cruiser with 12-7.5in/50 guns would make sense

The 7.5in/50 gun still has merit for a 1921 ship. The gun needs to be mounted in a turret. I would prefer a triple turret, rather than twin. The 7.5in/50 Mk.III weighed 15 tons 9 cwt and 3 qrs. The AP shot was 200 lbs. The rate of fire was 5 rounds per minute. I would put the gun on a 13,500 ton ship with a speed of 32 knots. The primary role would be commerce protection, although I could see a role in fleet actions, or at least in detached task forces (as they came to be known in WW II). I would retain a secondary armament of 8-4.7in/50 guns. I would have a 4in belt. If I didn't say, the ship would be built for the British navy.