Is the Moskva the most significant warship lost in war since WWII?
The only similar ship I can think of is the Argentine light cruiser ARA General Belgrano, first commissioned by the U.S. as USS Phoenix, which was sunk in the Falklands War of 1982.
ARA General Belgrano
Displacement: 9,575 tons (empty) 12,242 (full load)
Length: 185.4 m (608.3 ft)
Complement: 1,138 officers and men
Russian cruiser Moskva
Displacement: 12,490 tons
Length: 186.4 m (611.5 ft)
Complement: 480