There was some difference in the reasoning - 5 (including Roberts) said that Congress and only Congress could enforce this part of the 14th. The three progressives agreed with the result but didn't think Congress alone had the authority. They didn't say it, but it seems they were reserving the chance that a federal court could exclude. Barrett said the majority didn't have to go that far to resolve things for this election and so should have given. A more limited opinion to avoid concurrences.
But, 9-0, and broadly enough that no state effort to exclude Trump survives.