According to straight news accounts, not op-ed pieces, the majority decision stated that a provision that had existed for 50 years without change needed to be rewritten. They ruled that only Section 4 of the law was unconstitutional. Per CBS News:

In a five-to-four ruling, the court ruled that Section 4 of the Voting Rights Act is unconstitutional. That section of the landmark 1965 law provides the formula for determining which states must have any changes to their voting laws pre-approved by the Justice Department's civil rights division or the D.C. federal court. Nine states are required to get pre-clearance, as are certain jurisdictions in seven other states.
Chief Justice John Roberts wrote for the majority that Section 4 is unconstitutional because the standards by which states are judged are "based on decades-old data and eradicated practices."
"Nearly 50 years later, things have changed dramatically," Roberts wrote. "The tests and devices that blocked ballot access have been forbidden nationwide for over 40 years. Yet the Act has not eased [Section 5's] restrictions or narrowed the scope of [Section 4's] coverage formula along the way. Those extraordinary and unprecedented features were reauthorized--as if nothing had changed."

Also per CBS:

The court could have made a much broader ruling by striking down Section 5, which dictates that those states must get pre-clearance. However, the court decided that the Justice Department still has a role in overseeing voting laws -- if Congress is willing to rewrite Section 4.

Personally as a conservative, I applaud any time the SC kicks the ball back to Congress and says, rewrite this if you don't want us to throw out the whole thing. That is what they are supposed to do.

As to crying about a decision I didn't like as being judicial activism, I believe I may have said something like that about the Court not having the balls to throw out CDC decisions that impacted interstate commerce during the pandemic. Judicial activism isn't decisions we don't like. It's decisions that effectively write laws, usurping the power of Congress. Telling Congress to rewrite a section of an existing law is not that.