Could 6-inch naval guns return?

Could 6-inch naval guns return on surface combatants in response to hypersonic threats?

Possibly. A 6-inch system would be a manageable and meaningful capability increase over 5-inch guns.

The answer treats the 6-inch shell as a capable weapon and the shift from 5-inch as technically manageable. The extra calibre offers a meaningful increase in projectile effect without requiring an entirely new class of technology. Hypersonic threats could provide an operational reason to make that change. This would be an evolution of existing naval guns rather than the return of an unchanged historical cruiser battery.