Spoiler free question about ending selection

[19thperson]

So I came in knowing that the game had two endings. I also looked up which choice leads to which ending. I chose the what people seem to be labeling as the not-true-end first. Then I realized after dying several times at the first phase of the final boss that the auto saves had been continuing the whole time.

Once I get one ending, will the game give me an option to rewind to the point where the ending choice splits, or will I have to do a second run?

[Rowan Skye]

There's a backup save made before you enter someone's specific soulscape if you got to the ending and want to replay.

[mP3+Z]

You don't need to do the second run.
Once you beat the game, the save file will return to earlier time (earlier than ending choose, the time you can still visit all the maps).