What about the “real” people that will hate Leo for his actions if he did succeed? How would his colleagues react to knowing that he basically disregarded every principle of ethics just to go back instead of forward? How would his daughter react to knowing that the person she kept unsplit for his brilliant mind basically used that mind to nullify her sacrifice and everything good that went with it? How was he going to explain his actions to literally everyone else in the OG dimension?
I again motion to all existing questions about Akaba Leo can be answered by the fact of him being a solipsistic fascist. He wouldn't care. He's the exact and precise kind of person who thinks the ends will always justify the means, no matter how horrifying or unethical those means would be.
To Quote Senator Armstrong:
"Making the mother of all omelets here, Jack! Can't fret over every egg!"
(That and for all we know, the reversing of the worlds would erase anyone knowing, seeing as noone except Leo knew about The Old World, and only he'd and maybe Raye would have to care, and it's pretty clear Raye's actual feelings regarding the matter mean absolutely DICK.)
Leo was pretty upfront he considered his daughter's sacrifice the problem and NOTHING of value or good was generated by what she did.