Postal votes arriving at Election Central aren't legit?
I don't think you have thought this through. Even assuming you have zero experience working elections, if you consider the enormous conspiracy required for illegitimate postal ballots to be counted, it's either the biggest conspiracy in terms of participants or you have had a major brain fade.
I'm happy to entertain your thoughts on how those ballots would be counted, if they were fraudulent. Which they weren't.
Note that you are talking about one election central, but to fake a presidential election, hundreds of polling centers would be involved.
I hope you understand that every election has late ballots delivered for counting, as long as they are postmarked by COB election day. But, please, give us your conspiracy theory.