My point is that most content posted on these platforms is heavily modified to game and appease the algorithms that drive engagement. So you never really know if something is factual and honest.
Add to that the fact that these platforms promote content that is actively harmful to its users, and to society as a whole, and I doubt whether whatever valuable information is on them is really worth searching for and consuming. Chances are that you would be able to find the same information elsewhere, without risking your sanity.
That said, I do have an extremely negative view of all social media, and actively avoid it, so I concede that I may be missing out. :)
Outside of the chinanet this also happens, where Google, Apple, Facebook and Microsoft all try to keep you inside their ecosystems (to say nothing of the traditional media companies like Disney, WBD etc), but outside the chinanet there remains a small but influential "information wants to be free" movement that is unaligned with any government or corporation. So we have Wikipedia and OpenStreetMap and the Internet Archive... It's not much, but it's something.
From my perspective if people really want to see a free and open internet, where information is never hidden in gated communities, the only choice is to support non-profits with aligned missions. Then people all over the world - including China - can contribute.
It's kinda sad that stuff like Caltrain electrification, for example, has a huge and well-researched article despite not even being in service yet, just because of the large amount of Wikipedians in the Bay Area where the Wikimedia Foundation is headquartered. In the meanwhile, entire operational train systems both in China and elsewhere in the world that have vastly greater ridership, longer length, more advanced technology, etc, get nary a mention. I have nothing against Caltrain electrification getting a great article since I'm an inclusionist but it is just sad how little of the cool things, especially in China, are on Wikipedia.
Chinese topics are usually well-covered on the Chinese Wikipedia, the lack of an English-language article is more likely to be attributable to a shortage of English-Chinese bilinguals translating that information.
Do you have some particular train system in mind?
There's food, technology, science, whatever. I mean sure there's noise in the form of memes like all social media sites, but calling it "minimal value" is pretty extreme.
To take one example, I use Xiaohongshu to read about camera lenses. There's a lot of good information that's not available on Western platforms (optical simulations, anecdotes about rare lenses, etc).