Things that go entirely as the Constitution requires are still completely illegitimate if the left says so. And usually that’s shorthand for: The left tries to find a way to stop a perfectly constitutional process, the left fails, the left decides it had a define right to what it wanted and thus the perfectly constitutional result is illegitimate.
Ergo, Brett Kavanaugh, you may now be a real Supreme Court Justice, but understand: Your vote on cases doesn’t really count if it’s actually needed. There may be now be a majority of real conservatives on the Court (then again, there may not), but Kavanaugh has no business being there so no 5-4 decision with Kavanuagh joining the majority counts.