Why rebuild a British battleship instead of a Soviet design?

Why would the Soviet Union rebuild Royal Sovereign if it could instead construct its own battleships?

New designs would probably provide better ships, but converting a British imperial symbol into a Soviet vessel could have propaganda value.

A willingness to spend heavily on Royal Sovereign raises the question of why the Soviet Union would not build ships of its own design. If Soviet industry had become capable of completing its intended battleship fleet, new construction would offer more useful ships for the investment. That development could also encourage Western navies to complete their own late battleship projects. A separate political motive is proposed for retaining the British vessel: turning a conspicuous symbol of British imperial power into a Soviet warship. Under that explanation, the ship's propaganda value could outweigh its military efficiency.