Britain's MRSS approaches an armed LHD by degrees

How plausible is a hybrid littoral combat ship and landing platform dock?

Very plausible; Britain's MRSS concept is already evolving toward an armed amphibious aviation ship with landing craft, drones, and a large flight deck.

Britain's Multi-Role Support Ship work already makes the hybrid concept plausible. The design family combines a well dock, large helicopter facilities, landing craft, Royal Marines accommodation, and mission space for maritime uncrewed systems. Studies have also considered VLS, directed-energy weapons, a larger flight deck, and emergency F-35B operations. If realized, the ships would effectively restore an LHD-like capability by another name and offer a model for medium powers such as Australia and Canada that need several functions in one hull.