If China is "exploiting" DRC, it clearly is not going to pay for trees, that it can't get. Prosperous countries can give money to save some tress and locals will accept it and will also sell the tree to China - that's double profit ftw!
DRC is not governed by colonizers and is doing this on their free will. My people were oppressed by Russian Empire longer than DRC was colonized by Europeans and when they gained freedom, they in short time gained prosperity. It is an insult to the Congolese people, to consider them unable to think for themselves and make their own choices and sacrifices for their better future and that someone from US, who is not living in DRC has better understanding what is best for them.
Trees are not only producing oxygen, but they are also consuming it, so in total oxygen production value of trees around equatorial regions is 0. Threes might produce more oxygen further away from equator, only where days are longer, but they have never been a reason why on this planet there is an oxygen.
https://www.nationalgeographic.com/environment/article/why-a...
Hell, even when your country pretends to be a democracy, and is responsible for colonizing other countries throughout history and massacring countless people (like France/USA/UK/China/Russia/Turkey has), you don't have free will as a people and you will still be exploited by psychopaths who run the show.
If you heard about DAPL in USA, or NDDL in France, you may know it takes a certain amount of people and anger (and arguably molotov cocktails) to stop corrupt corporations and government officials from stealing your land and polluting everything.