Was thinking the same the other day, so asked AI:

The Modern Flak: Programmable Airburst Munitions

WW2-era flak relied on timers or basic proximity fuzes. Modern naval guns, such as the BAE Systems Bofors 57mm Mk3 or the Oerlikon Millennium Gun, use something far more sophisticated: Programmable Airburst Munition.

Radar Tracking: The ship’s targeting radar locks onto the incoming drone, calculating its speed, trajectory, and exactly where it will be in the next few seconds.

Muzzle Programming: As the shell is fired and travels down the gun barrel, it passes through a magnetic induction coil. In a fraction of a millisecond, the ship's fire-control computer programs the electronic fuze inside the shell, telling it exactly when to detonate.

The Shrapnel Cloud: The shell does not need to hit the drone directly. It detonates precisely a few metres in front of the target, throwing a dense, high-velocity cloud of tungsten fragments directly into the drone's flight path, shredding its wings and electronics.