Lacking that kind of leverage, economic leverage is really the best next thing isn't it?
This is true more so when the people didn't even elect this government.
You could instead not purchase goods from companies (not countries) that actively support China in exploiting these people. (like apple) https://www.businessinsider.com/apple-forced-uighur-labor-ip...
It's almost a Pavlovian thought-stopping response by now - "sure, we have faults but we know them already, can we now concentrate on treating the enemy as some unique evil again?".
West is much more transparent than non-West, so we have better chance to differentiate good parts from bad parts. If we don't have such opportunity, and we consistently get burned with bad parts, we're forced to assume the whole non-Westness is bad. Here "West" and "non-West" is somewhat similar to "USA" and "China".
If China would be more transparent, if West would see differences, and interactions between those differences, and could judge the parts by those interactions, the scope of blame can be refined. Similarly with more transparent West we can see evolution of society or its parts towards more or less cruelty towards each other and judge and act accordingly.
*edit, that should probably be 1975 because we pretend the Vietnam war never happened
https://www.npr.org/2020/09/18/914465793/ice-a-whistleblower...