Correcting claims about torpedo depth, silence, and easy kills

Could a totally silent torpedo launched from 2,000 meters depth easily destroy the battleship from 30 miles away?

No. The depth claim is implausible, torpedoes are not silent, and a long-range attack must defeat a wide ASW sensor screen, target maneuver, decoys, and active countermeasures.

The claimed launch depth of 2,000 meters is presumed to be a typo for 200 meters, since submarines such as the Virginia class do not normally operate at the greater depth. Under-keel attacks are an established technique, with magnetic detonators intended for that purpose in the Second World War. The proposed screen uses six uncrewed surface vessels with towed arrays, three on each side roughly 15 miles from the battleship. They would alternate moving and drifting as they leapfrog one another, while helicopters and rotary uncrewed aircraft deploy sonobuoys. A target crossing the attacker's beam at speed could leave the engagement area during a long torpedo run. Torpedoes are quiet rather than silent, so combined sensor data, decoys, and possible anti-torpedo torpedoes remain relevant. An illustrative spread of six or eight weapons might obtain one hit, or none.