Yeah, ideologically I'm no PRC advocate in the slightest... but I don't know an argument based in reality that says they aren't "the real China."

The Kuomintang / Chiang Kai-shek lost the civil war. There's really zero ambiguity to this. They lost all 4 of their capitals in a row, and were routed in exile to an Island that was literally handed over to them by the American brokered Japanese surrender. Even then needed the American's help instituting a brutal authoritarian martial law for over 40 years to suppress PRC popular sentiment.

That's not to say the PRC weren't brutal too but like... c'mon, an army who lost the war, were hiding in exile on an island literally handed to them, and needed foreign powers to help brutally suppress democracy for 40+ years because the people would just vote to join their enemies again can't possibly be called the legitimate successor state.