Let us just be real here for a second. The solution has already been thought up and planned. Just like a bad marriage, some time apart will make one reconsider life choices.
So let all the nazi's go to space, have their happy mars, 'The Expanse' style.
Then after we'll see how we feel about each other. Breakup or no, no love lost.
I get you. When we zoom out over history, change does actually happen, just at a slower pace than we like. The people below the current figureheads have at least slightly different plans and much less clout. Things are going to change soon. Few years, can't say exactly.
Edit: I am deliberately very general in this analysis.