I think that framing "Imperialism" as belonging to the past is inaccurate.

Many of the problemmatic behaviours grouped together into the term "Imperialism" have not actually stopped. There are Western developed countries that are doing horrible things to non-Western developing countries right now, and doing horrible things to their own people too.

I think a good first step would be to stop doing the horrible stuff now. If the problemmatic behaviour stopped, the topic of redress for past wrongs could be considered from a better vantage point. "I'm sorry I killed your ancestors and stole their stuff 100 years ago" tastes like ashes when coming from someone who is killing your family and stealing your things now, or who is doing something more subtle but equally awful.

"Disadvantaged" is a word that glosses over the damage done. Also, the whole question could benefit from being more specific and defining terms better.