Well first of all the indigenous nations as cultural and political entities still exist and still claim territory stolen by the settlers. The majority of settler owned land will be taken back into indigenous sovereignty. Many nations including the Americans and Black people will want to use the same resources. They can share through agreements reached in decolonial states. In my prediction, these states will be confederations between the peoples that inhabit and use the lands and resources in question. Equality of nations rather than equality of individuals will necessarily be the lower stage of Decolonization where individual equality will be gained towards the higher stages as the decolonial states wither away. Africans in the Americas are nations born into world through their struggle against slavery and colonization, but we must be careful reactionary ideas such as a Black Belt state as there are indigenous nations who claim and live in that region still.
Any system where Americans exercise political supremacy over colonized groups will necessarily reproduce settler Colonial relations. There will be no reforming the American annexationist system, only the the de-fanging of their previous annexations and thus their access to further annexations and Imperialism.