The first point is false, if millions were actually in concentration camps the evidence would make it obvious, there would be no controversy. There are also many other Muslims in China apart from the Uyghurs that enjoy freedom to worship. How much do you actually know about Xinjiang's history and it's relationship to Afghanistan/global terrorism? History and nuance are extremely important in these conversations and seem to be completely missed by the majority of westerners.

I'm not well researched on the South China Sea issue but they definitely do not claim the entire thing for themselves. The lines are indeed blurry regarding this area due to its history of colonialism and war. As far as I know it's perfectly legal to build islands if they want to, at least their military bases are defensive and close to their homeland unlike some countries.

The Taiwan issue is incredibly complex and historical but as far as I know the Chinese government pushes for peaceful reunification, not invasion. To the Chinese, Taiwan is a part of China and so are it's people, they are brethren, they do not want to kill and invade them.

I don't have an opinion on whether or not it's legal to execute criminals in China. I'll just say that many in the west support capital punishment and many other countries besides China continue to practice it today. It doesn't make them an evil regime.

As for the war, due to geography China is inextricably tied to Russia and hurting that relationship would hurt the Chinese citizens. I think the government is trying to approach the situation with caution and doing whatever works out best for their own economy without "taking sides". Ultimately it's not their war and they don't want anything to do with it, it's a net loss for them whether they support Ukraine (lose Russian economic activity), support Russia (get shut out by the west economically), or stay neutral (people like you see that as supporting Russia anyway)