When a new timeline diverges sufficiently to hit the red line, that means it's diverged too far to be reined in with a few reset charges, and is now a full-fledged alternate universe. But even in the time before it reaches that point, if someone manages to somehow skip out of that divergent timeline, as Loki did using the Tesseract, that person becomes a rogue variant and needs to be hunted down, before their actions beget yet more divergent timelines.
They do potentially have access to every puny mortal weapon ever created in any timeline.