Pence's role in the process is defined by the Constitution and by law. He presides over the count. He has no power to accept or reject electors or to challenge slates of electors, only Congress can do that. His role is purely ceremonial.
His power in these matters is PLENARY: full complete and covering all matters.
Read it and weep.
Perhaps the supremes will need to take up the definition of plenary after 1776.