do indigenous ethnic groups count or no? china and India together have a few hundred indigenous populations that didn't get genocided, and a few hundred that did (most before 1900 for stupid reasons). Canada succeeded at almost all of theirs, the west is really good at getting rid of things they don't want, China tries to construct systems that please them without giving them real power, which is also evil but definitely beats 'killing the indian and saving the man'

it would take several classes to understand diversity in China because of their government system and long history but this English wiki article is a great start

https://en.wikipedia.org/wiki/Ethnic_minorities_in_China

I've always found that it's better to just focus on what people are likely to become invested in rather than expecting them to read everything. this is a much shorter article, read this one instead:

https://en.wikipedia.org/wiki/Kyrgyz_in_China