You're right that the Supreme Court does not fix legislative branch issues. Beyond that, I'm afraid you've fallen for "extremist, activist" narratives that are debunked by the record of the US judicial system, if not basic civics itself.
No, it is complete nonsense to say SCOTUS dealt a blow to the VRA, and any outfit saying such a thing is either lying or amazingly ignorant as to what the ruling, and the act, actually said.
Read the opinion. It lays out that it was reinforcing the VRA, supporting it on its terms, not dealing a blow to it.
This ruling came about BECAUSE of the VRA, as court after court observed.