The event is now live. :O

[Iscah]

Actually, there is a way you can get that content, but I don't think they would do that because of technical reasons but New Game + would be a good place imo.

That doesn't answer my original question (where was all this alleged additional content I don't recall from the 2018 Rising event) but also doesn't make sense in itself.

If the way to get this content is so cryptic that you can't even tell me what it is, it is clearly not in the game.

And New Game Plus is for replaying content that currently exists in the game, which 1.0 content – if that's what you're alluding to – is not. But you aren't explaining yourself so I can only make wild guesses at your meaning.