Just to expand on this, there are parts of the country (Atlanta, Houston, DFW) where Section 2 helps the GOP more than it hurts them.
On the whole, i think the decision is more bad than good in terms of minority representation, significantly so even.... but, for instance, if state lawmakers in Texas were, in practice, to eliminate the VRA vote sink district that spans between Fort Worth and Dallas and allot it to other adjacent districts, it would potentially be a net negative and could potentially put a couple of districts that are 15> GOP in play.
A ruling against Section 2 seems like it would be symbolically pretty terrible, but how it would play out in practice would just vary based on the geography.