When South Africa dismantled apartheid, it did not end with the expulsion of all white South Africans. They became part of the new South Africa, just without the criminal discriminatory oligarchic powers the apartheid goverment had. When Bolivia recognized its indigenous heritage and became a plurinational state, it did not mean that people of European descent were expelled in masse. It meant the recognition of the previously discriminated indigenous and mestizo people of Bolivia and the beginning of a path of integration and revalidation.
What I mean is that it's ridiculous to think that decolonization inherently means mass suffering and relocation, that's what colonization does. Decolonization is recognizing the crimes of colonization, but more importantly, material, political and social steps to give power and self-determination to the exploited native people who were victims of colonialism and imperialism.
In multicultural societies, you don't go like in that Peter Griffin meme with a skin tone chart and saying 'well, you go back to Europe, you go back to Africa, you stay here'. You build a new society on the paradigm of dignity for exploited people and equality under the law. People are acting like this is some sort of fantastic utopia instead of real initiatives that were done in living memory, with successes and failures, as all such initiatives have. One must ask why are some so insistent that multicultural societies can't thrive, especially when for most of history, societies were indeed like that. Consider why you think like that.