USNS?
United States Navy Ship. A non commissioned ship owned by the navy.
Military sealift. Manned by civilian crews IIRC.
United States Naval Ship = non-combatant, fleet auxiliary vessel designation. Typically a mixed Navy, Merchant crew from what I’ve seen & read.
United States Ship = combatant
US Naval Ship - typically manned by a Merchant Marine and/or civilian crew with a Navy Liaison on board (at least up till I got off active in the mid-90s) for classified communications and such. Almost all replenishment ships are of the USNS variety.
United States Naval Ship.. essentially the Military Sealift Command... crewed by civilians.