My problem was the Janeway was the only one who could save the day thing, thats what exagerrates the importance of her existence
But Kirsten's explained that. It wasn't about Janeway personally being extra-special. It was about the notion that altering history had unpredictable consequences. Admiral Janeway chose to change history to get her younger self home sooner, and that undid an event where Voyager
happened to be in the right place at the right time to solve this cosmic crisis. So Q Junior decided that the only way to put it right was to put all the ingredients back in place where they'd been in the original timeine, and that included Kathryn Janeway. Everybody's gotta be somewhere, and it was just by luck that Janeway and Voyager
were in a position to deal with the problem in the original timeline. But because Adm. Janeway undid that event, it created a problem that could only be solved by putting Capt. Janeway back where she'd been originally.
So it's more than anyone's
actions and choices could turn out to have a domino effect that's crucial to the shape of history, so changing the past of someone who doesn't seem all that exceptionally important to the cosmos could end up having far greater consequences than could've been foreseen.