Because it's so far off, I would be certain that BA won't know the answer to this, let alone anyone else. So much has changed. Even just over a year ago travel to the USA from the UK involved significant hassle and expense in terms of testing, masking and vaccination requirements, whereas by the time you travel this may all have gone completely for UK-USA. China has been on a different path, but the clear direction now is towards easing restrictions.

If this was for a few weeks off, I'd suggest you consider post 268 in this thread, and perhaps the VeriFLY thread, as a possible way forward. It works in some but not all cases.
https://www.flyertalk.com/forum/brit...l#post34983129
(may take a few seconds to load)
There isn't much you can do here until about a week before departure, but obviously keep an eye on China's restrictions in the mean time. Visa + visa-free travel documentaiton was always carefully checked before the pandemic for China, in common with many similar countries, but that usually doesn't stop you doing OLCI.