I don't know how true it is, but allegedly[1] the algorithm of tiktok in china is tuned to promote achievements and education, while in the western world it promotes debauchery and stupidity. Doesn't take a huge leap to think it could be intentional.. [1] https://www.opindia.com/2022/07/tiktok-china-engineering-oth...
On TikTok you largely just get more of what you've already engaged with. If you're using the platform for porn you're going to get a lot of it. If you like and engage with scientific/political content you'll rarely, if ever, see a video of someone dancing.
edit:
It's anecdotal but having taken a look at TikTok's web feed: https://www.tiktok.com/foryou. The content there was less sexual than the purportedly sanitised Douyin.