Seapower implies the country is not afraid of conducting constant naval warfare. That is difficult in the era of nuclear weapons. Say country A attacks country B's ships, the proper response might be sending ICBMS to A's capital, not another naval war.There have been civilizations that have tried to gain power and prosperity by "ruling the waves." Examples of these seapower states would be Athens in ancient Greece, Venice during the dark ages, Portugal in the age of discovery, and most famously the British who built an empire where the sun never sets. A seapower state puts "all of its eggs into one basket", the Navy. A continental power would be the opposite. Its power comes from the land not the sea.
China historically has been a continental power.
Question, can China ever become a Seapower State?
So the navy is really used by large countries against small countries. It's even questionable if US navy and PLA will fight directly over Taiwan, because nuclear escalation is truly out of control when that happens.
But when China fights a small country far away, that is when power projecting is necessary. So yes China is a seapower already, but not in the traditional sense. Remember China is not US 2.0. China does not want to go to war with anyone unless being pushed like in 1962