In addition to everybody’s excellent answers, here’s a little sample platter of things to further drive the point home:

-China is pursuing green energy, green cities, environmental sustainability–not just talk but lots and lots of walk. Capitalist governments are constitutionally incapable of serious green initiatives of this size and effectiveness.

-China does not surpress leftists (except the type of Western-esque “leftists” who are at best useful idiots for the CIA to undermine China with), figures like Marx and Mao and Lenin etc. etc. are celebrated and the sciences they created are taught and expanded upon. Chinese youth have been having a massive anti-consumerist culture wave that the CPC is certainly not suppressing, the return to more ideological Maoist thought has been welcomed.

-China, as opposed to popular Western narratives, is not imperialist and goes to great lengths to build mutually beneficial relationships with vulnerable countries that an actual capitalist country could hardly stop itself from brutally exploiting.

-China is not directly operated by workers like the Western utopian conception of a binary socialism that just automatically switches on, but the people of China overwhelmingly support the CPC and are very satisfied with how it operates, especially on a federal level (we’re talking percents in the mid-to-high 90s, reported by Western NGOs even). Likewise the Chinese people in identical numbers report feeling like their country is the most democratic nation on the Earth, and there is a strong sense that the Chinese working class steers policy; this is why there have been such huge economic boons for the working class in China lately, if it were up to a separate class of politicians out-of-touch with people on the ground who did as they pleased then there would be no reason to not continue with the Dengist mode and strive for productivity and development with no such increases in living standards.

-Living standards-wise, they have elicited extreme poverty, have the fastest growing middle class in the world, the largest proportion of out-of-country vacationers across the world, Chinese workers of all fields these days regularly look forward to incremental increases in their real wages and work/life balance, etc. Again, all of this is impossible under capitalism, except perhaps social democratic concessions which are given under extreme duress when the ruling class feels it must placate the working class to prevent revolution; the Chinese people didn’t have to murmur threats of violent revolution to get treated well.

This tidbits are just surface level and go a lot deeper, and all these issues interconnect to clearly show that China is indeed socialist. Capitalism and capitalists are just tools to the Chinese who see it/them as necessary to their long term plan of building socialism. Of course after Mao and during Deng and onwards the economic reforms led to truly pro-capitalist forces within the CPC, which went hand-in-hand with the corruption and capitalist accrument kf power of that era, but this was an expected side effect of the Dengist operation, and after they succeeded in their economic goals leaders like Hu and Xi then made sure to uproot said corruption and re-supress said capitalists before they riddled the CPC and eventually led to a USSR type scenario and capitalist coup attempt. China has always been socialist and at this rate always will be, there was definitely some pressure exerted on them as they undertook this long game to secure a life for themselves and to thwart Western hegemony and, who knows, there might be a nearby alternative history in another universe where the corrupting forces slowly weaseled themselves into more and more power and socialism in China was destroyed, but this is not the case.