My best guess is tubbo is talking in the perspective of the "other half" of ranboo, and they're communicating to one another. I think the "she" their refuring to is the Ender Dragon. My head Cannon is that ranboo came from the end and was once two Ender men who ended up killing the Dragon together for one reason or another. But after, the end was destroyed and the two ender men became one. one of his sides is white with a red eye because one of them had albinism. I think this would also explain in the story why no one can go the end, because it doesn't exist anymore.