Drone swarms at sea are different from the land kind as there's no terrain to hide behind.

Aerial drones can be small enough to not register on radar, especially if they're wave-hugging. Sea drones appear to be very low profile, and hard to detect. The Ukrainians have demonstrated the latter several times (most recently penetrating a Russian naval yard and damaging a submarine).

It will be interesting to get details on what is actually deployed (ref: laser). The best information I could find says it was not mobile (Iron Beam) because of size and power issues. Maybe they've sorted that out. They don't have to worry much about ship-mounts in Israel. They are using it (or intend it to be used) as part of their Iron Dome. So, size doesn't matter too much. Just enough power to destroy a target before it can hit its objective.