I would recommend a de facto independence, like Switzerland, that is so devolved politically, each canton is almost like an autonomous region, they can then just divide the oil wealthy based on % of population in each region. The problem is that Iraqis, I don’t believe are as “civilized” as the Swiss. They also don’t have the motivation. Switzerland came together, not out of like for each other, but because they did not want to be taken over and ruled by larger powers, they saw that a Zero Sum game was not going to work and they had to work together despite linguistic and religious differences. Iraqis are not in that situation and don’t have such a mindset (not in mass).