That's some very obtuse thinking.
The US has been applying soft power and hard power in South America - to put it euphemistically, as the most recent US intervention was just days ago - for close to a century. The Chinese... haven't.
Why should people in South America give a shit about Tiananmen or Tibet and at the same time not give a shit about the escalating authoritarian grip of the US regime, which is infinitely more relevant to their lives?
How can you say the Chinese "haven't"? They've been using soft power for some time with Venezuela. They've been importing Venezuelan oil. They have been making loans as well. The loans a are a huge part of "soft power". They've also replaced a lot of items impacted by Trump's tariffs from South America.