Is it possible for me to buy a piece of land in Africa and build a China immigrant country?

Your idea is very good. I've learned it before.

There are many examples in the world, mainly in the Caribbean, Europe and Australia, where people have established micro-countries in private places.

But in the end, for different reasons, there was no long-term success.

But I think if you really have this idea, you can consider Africa, the Caribbean, Oceania and so on. Subsidize a federal state, or a small city, and then lobby for legislation to allow an institution (headed by you or your trustee) to approve chartered immigrants.

Then, with a certain number of immigrants, you will be elected governor or mayor.

Then, by voting, you will become the head of the country, or lead the state or city to fight for independence. After independence, you will be an independent country.

If you are interested, we can talk about it in detail, because I am also interested and have done detailed research before.