@Positron (or any other Chinese Kiwis), feel free to correct me if I get any of this wrong.
China never really converted to any of the Abrahamic religions, or any organised religion for that matter (despite the best efforts of Fr Matteo Ricci, Nestorian preachers, various Muslim khanates, Manichaeans and the Kaifeng Jews). Part of this is because the Chinese Emperor, a bit like the Emperor of Japan during WW2, claimed to be the Son of Heaven which didn't really mesh well with Abrahamic views on kingship, and part of this is because Abrahamic religions' spiritual centres were several years' travel away and so nobody from them really bothered to send missionaries to China. What this means is that most Chinese people still practice Chinese paganism, Taoism, Confucianism, Buddhism or some mixture of those four faiths.
What all four of those religions have in common, especially in China, is that they all include a thing called qigong in their religion. Qigong is basically a cross between yoga and martial arts. During the Cultural Revolution Mao promoted qigong in hospitals because it was Chinese, cheap and he saw it as a form of alternative medicine. Eventually it became popular in Chinese society at large and throughout the 70's and 80's the CCP promoted it.
I'm going to go on a tangent here and explain something that'll be useful later; the CCP has no problem with religion
per se. The CCP has a problem with religion if your religion makes you "disloyal" to the state. China has no problem with Christianity in and of itself, China has a problem with churches that preach against the CCP or which appear foreign - which is why the CCP and the Catholic Church have never had a good relationship; if you're a good Catholic your first loyalty is to Rome, not to Beijing, and the CCP have never liked that idea. It's also why the CCP is imprisoning Uighurs; Uighurs are Muslim so don't want to live under a secular state, something the CCP also doesn't like.
With that in mind, the CCP saw no problem with promoting qigong because many of its members follow a "Chinese" religion (even if they are officially an atheist party). Plenty of groups were set up to practice qigong. One of these groups was Falun Gong. At first the CCP got on well with Falun Gong and many CCP members also practiced Falun Gong. Eventually, the CCP decided to suppress Falun Gong, in part because:
1) Falun Gong was refusing to join a CCP-run qigong organisation and effectively to submit to the CCP
2) It had around 70 million members in China alone, which made the CCP think that it was a potential rival
3) It preached against the CCP, which is a big no-no.
4) It is, to put it frankly, a cult.
After Falun Gong was suppressed in China proper its leader moved to a small town in upstate New York and set up a compound there. This is where it really starts getting like Chinese Scientology. Falun Gong basically run that town and their leader is very much a L. Ron Hubbard-style cult leader. They believe that aliens exist and invented communism, computers and miscegenation, and that Heaven is divided into sections for each race. They're also into Q tard stuff and believe Trump was sent by God to save China from communism. Basically, they're no different to any other cult and the only reason they have such a good rep is because they present themselves as anti-CCP activists.
Falun Gong claim that China harvests its members organs and sells them on the black market. I don't know how true that is, but I'd be encouraged to take it with a pinch of salt given that they are a batshit cult that hates the CCP.