Ukraine

It gets and keeps him away from Russia, so there won't be a repeat coup, so Putin feels safe. It puts Pregoznin in Africa, surrounded by his people, and maybe getting him far enough away from Putin that he doesn't fall out of windows anytime soon. His men stop getting slaughtered for Putin's ego, so they 'win' as well. And with Wagner out of this war, there's more hope for Ukraine as well.

And, as you point out, the big losers here are the countries that Wagner is active in: Central African Republic, Libya, Mali, and Sudan. Hopefully, the coup will break the support that Russia's been giving to Wagner in Africa which may lead to them being extinguished there as well.