The exact same reason you discuss for not starting a new country is the same reason I oppose reparations. It is like an insurance settlement where you get paid but give you any rights to come back later and ask for more if you find out you had lingering issues. Reparations are like giving us a stimulus check during the Corona virus and acting like that solved the problem. Reparations don't fix the problems of racial injustice and are a payoff to avoid the system changes that are needed for true equality. I would rather you take the reparation money and invest it in programs that help people who have been disadvantaged become productive citizens that contribute and pass along their new found success with others. Take a welfare family where mom wants to work but a full time job at minimum wage (30 hours a week so they don't have to pay benefits) doesn't even pay daycare for 2 kids let alone medical, food assistance rent relief and other benefits you get under welfare. So what choice does she have? She needs a parent advocate to help her explore her options, programs which.help her get back on her feet educationally or vocationally, universal healthcare and universal daycare, and a living wage for a full 40 hours if she wishes to work full-time. How a reparation payment be anything but a symbolic gesture of guilt and admitted harm. If these past few months haven taught us anything, we have seen that action and systemic change are needed. Payoffs aren't the solution other to assuage guilt.
If Biden wins forget 2024, Dems are going to sleep in 2022. The exact same thing happened in 2010, 2012, and 2014 when the Republicans clawed Congress back, systematically took over a bunch of state governments, and then got Trump elected. They're masters of this kind of long game.