Sadly, the Legislative branch of our government, and perhaps even the Judiciary by acts of omission, has certified Biden is the legitimate office holder. It just doesn't get more legitimate than that. To argue otherwise is the ramblings of a madman (especially if they are an experienced attorney)
Of course, that legislative certification may be subject to review just as the Judiciary is able to conclude other legislative action is unconstitutional.
A certified fraud. Oxymoron.