The challenges and objections are part of the Joint Congressional rules, as accepted in the Agenda for that event.
They are not a Constitutional requirement.
Article 1 also states, “Each House may determine the Rules of its Proceedings,...&c.”
And following the rules is part of the Constitution.
And as I remember Pence handed control over to Pelosi which violates this clause:
“The President of the Senate shall, in the presence of the Senate and House of Representatives, open all the certificates and the votes shall then be counted;”
They also did not open or deal with the alternate certificates which means they did not open them all.