If it helps at all... I've been looking over some of the research Tony and my dad have been doing, and honestly? I don't think we're changing anything. In fact, I think we're just expanding the multiverse. Like... creating more timelines to tack onto the whole thing.
Think of it like this. Let's say reality was a four-lane highway. Us showing us was like the equivalent of a road crew showing up and turning it into a SIX lane highway. Rather than making traffic worse, it just expands it's range.