The Borg were only 2 years away from a star base at Enterprise’s maximum warp. We know they can go faster, and that they used warp conduits.

We can probably say within 2-5 years the Borg would have found almost all Alpha quadrant major powers, and likely would have overwhelmed at least some of them.

Voyager established Borg presence in the Alpha quadrant decades before Q who, at least, and Enterprise had them on Earth centuries ago.

Wasn't the start of that episode the enterprise trying to ascertain why some outlying colonies had gone dark? The borg were just studying the federation at that point; if they'd had more time they could have become even more dangerous