About those "boulders shaken loose" by the Dart impact. I don't think we really know how many and where they all went. We have been told that the DART impact could not make any new hazards to Earth, because we were just changing the orbit of a minor satellite orbit around a minor asteroid. But, if we have sent "boulders" that were "shaken loose" by the impact into INDEPENDENT solar orbits, I don't think we know that their new orbits are, and whether they intersect Earth's orbit.
Probably not a big deal for the size of these "boulders" from this impact. But I think it is something to seriously consider for any future tests, especially if those tests involve higher inertia transfers or more explosive energy transfers, or targets that more closely approach Earth's orbit.