It is true that any PRC citizen could
potentially be President (of China), just like any USA citizen could potentially be President (of America).
The key word is "potentially".
The CPC is a reincarnation of the Imperial Chinese system. It is open to all citizens but it is fundamentally a meritocracy, meaning only the smartest can thrive. Because of the limited positions available, only the strongest survive. During the Imperial era, Confucianism was the ideological measuring stick. Today, it is Communism, or rather Socialism with Chinese Characteristics.
Because of this "filtering" system, China is strictly speaking not a democracy, at least by its common definitions, i.e. a direct democracy. But how many direct democracy systems are working out there anyway? Most countries that claim to be democratic are not democratic either, and I am not talking about the Democratic Republic of Congo or Democratic People's Republic of Kim... err Korea.
Model democracy USA has a complicated electoral college system attempting to implement representative democracy as a gateway for direct democracy. The intention is that all men are equal but the result is some men are more equal than others. Case in point: The 2000 Presidential Elections, where Al Gore had more votes than G.W. Bush but Bush won because of the Florida state vote. Stalin said it best: It is enough that the people know there was an election. The people who cast the votes decide nothing. The people who count the votes decide everything. Was it a coincidence that the Governor of Florida was the brother of G.W. Bush? Was it a coincidence that the conservative-majority Supreme Court stopped the recount?
While theoretically any US citizen could become POTUS, if you don't have the resources to campaign, you have zero chance. I bet many Asian-American children, like many other US children, dream of being President when they grow up, but likely in their lifetime, it is not possible for an Asian-American to sit in the White House. Assuming racism is not an issue (haha), the biggest barrier is connections.
So basically you need smarts, connections, and money to get into the "democratic" system. Just like China, except the money requirement is less significant; in fact, it could be a negative.
All democratic systems start off as closed systems that opened up because the ruling class found the incentive to do so. China's system is designed to be completely open from day one. But as you get closer to the top, any system looks less and less like democracy and more like a game of thrones.
(In my writing, "men" is for human, not just male humans.)