I'm not sure where you get this notion that China is not a democratic country. First, people who actually live in China seem to disagree with you. In fact, far more people in China think that their country is more democratic than Americans think US is.
https://www.tbsnews.net/world/china-more-democratic-america-...This page explains how grassroots democracy and public participation works in China. https://news.cgtn.com/event/2021/who-runs-the-cpc/index.html
This is a good overview of how the party is structured, and how people participate in the governing process. This is fundamentally different from how electoral parties work in western countries. https://news.cgtn.com/event/2019/whorunschina/index.html
The party in China is predominantly composed of working class people as opposed to a ruling political class as seen in the west. This goes a long way in helping ensure that the interests of the government align with the interests of the working majority http://www.chinatoday.com/org/cpc/
Furthermore, a study spanning many decades of US policy shows that US can hardly be called a democracy in practical terms:
What do our findings say about democracy in America? They certainly constitute troubling news for advocates of “populistic” democracy, who want governments to respond primarily or exclusively to the policy preferences of their citizens. In the United States, our findings indicate, the majority does not rule—at least not in the causal sense of actually determining policy outcomes. When a majority of citizens disagrees with economic elites or with organized interests, they generally lose. Moreover, because of the strong status quo bias built into the U.S. political system, even when fairly large majorities of Americans favor policy change, they generally do not get it.
https://www.cambridge.org/core/journals/perspectives-on-poli...