All non-Chinese social media companies have to do is comply with Chinese censorship laws. Nothing ever stopped these companies from operating there except the filtering requirements was onerous (read: expensive). China brought in mass human moderation way before it was deemed necessary on non-Chinese social media. The primary reason FB, twitter was banned is they refused to filter calls for ethnic violence post 2009 terrorist attacks in China. Western platforms finally recognized that was necessary in the last few years.

The real problem is the disparity in allowable speech on between ecosystems means China can conduct official diplomatic influence campaigns on western social media platforms. Where as embassies in China frequently get censored trying to conduct influence operations. Really that's China exploiting an asymmetric western vulnerability, not much to do but fight fire with fire at the cost of western values.