China

Multiple considerations:

1. On authority: in a superficial analysis if 60% of a population vote one way and 40% vote another then 60% have authority over the 40%; and this authority is ultimately backed by violence.

2. On liberal democracies: what if despite the above procedural mechanism the governing apparatus ultimately is beholden to the capital class? We could then describe liberal democracies as democracies for the capital class and authoritarian on the working classes.

3. On voting; is voting every few years for a party that comes to power that makes decisions outside of the control most of the population really consider a democracy for the majority of people? What about democracy on where funding is invested in your local towns or district? How about democracy in your workplace? How about democracy in foreign policy?

4. Could other types of democracies exist? One would need a governing system that is then more powerful than capital. How would this look like? What if there was a system where people voted on policies rather than wasting time and resources on selecting a party who may ultimately not be responsive to their needs?

5. On power; the concerns about concentration of power is the accumulation of wealth at the expense of the population. One would then have to consider what kind of democratic feedback loops are in place in countries like China where they have lifted 800 million people out of absolute poverty in the shortest timescale seen in human history and continued an accelerated development?

Here is a paper by liberals attempting to figure out why an "authoritarian" country like China is significantly more democratic than a liberal democracy that is well worth a read:

https://www.researchgate.net/publication/303554342_Explaining_high_external_efficacy_in_authoritarian_countries_a_comparison_of_China_and_Taiwan

We examine the puzzling phenomenon that authoritarian governments are perceived to be more responsive than democratic governments. By comparing China and Taiwan by both large-N statistical analyses and in-depth case studies, we show that the answer lies in the differences between democratic and authoritarian institutions. First, failing to elect one’s preferred candidate in democracies predisposes voters to critical assessment of government responsiveness. There is no such predisposition in authoritarian countries where elections are nonexistent or nominal. Second, elections incentivize democratic leaders to over-respond to certain groups. There is no such mechanism in authoritarian countries. Third, the solid and clear legitimacy established by electoral victories shield democratic leaders from particularistic demands made through unconventional channels. Without such legitimacy, authoritarian leaders are compelled to cement legitimacy by increasing responsiveness.

I would also look at, if not already done so, RedSails' excellent primer, which touches on the needs of a vanguard party and democratic centralism:

https://redsails.org/why-marxism/

TLDR: socialist countries like China aren't just different types of democracies to the West but they are also significantly more democratic than liberal democracies.

(Hopefully the points the above help - some of which have been explored deeper in comments before mine)

Addendum - one may need to define capitalism; an approach is to consider that socialists differentiate capitalism from commerce and consider it an arrangement of production in contrast to other arrangements of production such as feudalism and slavery. It also noteworthy to consider capitalists as the "high priests" of capital; it is not sufficient to assign blame to a "few bad apples" - the structures that affords this class their power needs to be addressed.

Edits: spelling/grammar/formatting/clarity