All I really got from the interview is he was specifically asked about the 8th Umbral Calamity timeline, and on-the-spot, made a comparison to it and the present we play in being like two different branches of a multiverse. That's not really confirmation of anything to me, especially not that the writing team is crafting stories around it in the near future or that's it's any confirmation of something bigger than what we already know about the 8th timeline's existence.

If we're really being honest, 'Interview Naoki Yoshida' is not at all a reliable source of game lore. This is the same guy that was asked at the media tour what lore to go over to prep for Dawntrail and responded with two things (The names of the Convocation, and Myths of the Realm) that had literally nothing to do with the MSQ at all.