This is something that is introduced in Philosophy of Morals courses (usually a 2nd year philosophy course) as a known failed idea, unfortunately. It's called the Veil of Ignorance
WP.
Here's where it breaks down... If the premise for prejudice is a sincere belief that it's the best outcome, then people simply build the new society the same way as before.
For example, if I'm a person who sincerely believes that whites make better decisions than POC, and men make better decisions than women, then I'll advocate for a new 'perfect' society that would disenfranchise me as a woman POC, because I honestly believe
it's in my best interest.
The model relies heavily on all parties having objective, shared, facts. Which is not the reality of our world, unfortunately.