IMO China has learned from its own Mao era failures, the failures of the USSR and in particular the economic pressures brought by the USA on the USSR economically.
If as you say that Communism doesn't work or at least that China's form of communism wont work now, then why is the US using enormous economic resources to stymie China's growth. If the US really believed (as Marx said about capitalism) that communism has within it the seeds of its own destruction, then the US would let China be and self-destruct.
IMO you are confusing politics with economics and in particuluar giving too much weight to the US 2 party political system vs that of the one party Chinese system and their impact on their respective economies over time.
China's Hybrid economy (roughly 50% SOEs and 50% Private enterprise) has done well over the past generation and despite its current US prophets of doom, its fairing much better than that of the US at present (eg: Net growth...GDP growth minus inflation)
In science we accept that the data tells the tale as it also should in economics but of course there are those who smuggle in a political agenda and then make what is a moral judgement rather than a data based assessment .
The US erecting trade barriers is an obvious admission that its system is falling short of global economic standards (Trump even tried to impose crippling import tariffs on our meagre exports to the USA !) This resembles the British mercantilism towards the end of its empire.
