cielaqu: China's video games market is worth at least twice as much as USA's. If BG3 will be banned in China, it would be a big financial blow. Looking at Wolfenstein, GOG doesn't have problems releasing different versions of one title.
It's all speculation here, regardless. You can buy it now and hope, or wait until someone else finds out for sure.
As a developer, the easiest way to implement content censorship would be to turn on modesty filters by default, and ship the Chinese versions without the ability to turn them off. All of the content would still be present in the game files, though, so a clever modder could easily just go back and re-enable those options.
Making a completely separate build, with different cinematics, etc, for different countries, adds quite a bit of maintenance complexity. I'd imagine most developers would want to avoid such a thing.
That said - if you want an uncensored version in English, just use a VPN and pay in dollars to get a US version. Problem solved.