I saved in the incorrect slot…

Hey, I was playing a brand new game of NieR Replicant to achieve all the endings again, i wanted to get all the quests done before part 2 but I accidentally saved in the same slot after the interlude between parts. Should I finish the side quests of part 2? or should i just finish this playthrough for ending A and just start a new one…. I remember most of the requirements for the endings, thats why im thinking of just starting a new save file and do all the quests on it after.