It ultimately depends. The one path that's heavily affected is the Yandere path - it's now much harder to get on the Yandere path because the Yandere path involved 'dumping' Glade at first by sleeping with someone else. Now that you can't switch between paths, suddenly, the Yandere path is no longer viable on many routes. There are still a few routes that will lead to the Yandere path but the conditions to get to it are a lot stricter than before.
Similarly, some other paths have stricter conditions. For example, before you could invite Lorelei to the Ball before deciding later that you liked Kasula better. So to get the "Kexplorer" ending, previously, you didn't need to invite Kasula to the Ball. However, now because you can't switch, you have to invite Kasula to the Ball to get the "Kexplorer" ending. However, I imagine most people doing a "Kexplorer" run would've invited Kasula to the Ball anyway, so they won't have to re-do their saves.
Because it's easier, I'll make four separate lists for you:
Won't have to re-do: Kunity (Kasula Pregnancy Path), Lethrothal (Lorelei Betrothal Path), Throuple
New Endings: LLamour, GLove
Might have to re-do: Kexplorer (Kasula Explorer Path), Life (Lorelei Court Path), Girate (Glade Trust Path)
Will have to re-do: Gandere (Glade Yandere Path)
Hopefully this helps
As mentioned above, you unfortunately will have to re-do your yandere save, but the rest are safe.