I don’t see how other material overrides Destiny lore. We have our timeline, the alternate timelines and some extra dimensional planes. Alternate timelines are dismissed as unimportant. The planes are separate from the alternate timelines. So we aren’t changing universes. That’s why it’s a loop, if she was going to other timelines or universe things wouldn’t be the same every time. There would be differences to account for the different choices and outcomes. Like how in the Dark Futures our Guardian falls to corruption. But since she helped us in 1, we avoided the corruption. Everything plays out differently. Who says she needs to be a Lightbearer to hook up to the device? She is paracausal already, she wields Darkness. She isn’t looking for a specific moment in time. She said she every reset goes back to the same place with the same things going on. It’s up to her to find out what to do differently to get to the win state. That was the basis for her D1 background. She popped in and out of our timeline to alter things, that’s how she was able to be there to watch us when we were revived. Now her background is changed to forced loops.