Actually it was Congress that certified those votes . Many states had sent duel electors that were accepted in the past but were ignored in this election. And where was all this pull up your big boy pants when The Democrats had a special prosecutor looking into something as absurd as Russian collusion for the first two years of the Trump presidency ?
No State sent dual slates of electors in the 2020 election.
The GOP electors sent themselves. It was a publicity stunt that was as legal as if the Green and Libertarian party electors had stood outside the State Capitols along side them and sent themselves too.
There may have people in some states who got together and claimed they were the real electors for the state, but none of them had legislative approval. Not a single state sent more than one approved slate of electors.