"Therefore, the true opinion is the fifth, according to which the Pope who is manifestly a heretic ceases by himself to be Pope and head, in the same way as he ceases to be a Christian and a member of the body of the Church; and for this reason he can be judged and punished by the Church. This is the opinion of all the ancient Fathers, who teach that manifest heretics immediately lose all jurisdiction, and outstandingly that of St. Cyprian (lib. 4, epist. 2) who speaks as follows of Novatian, who was Pope [antipope] in the schism which occurred during the pontificate of St. Cornelius: "He would not be able to retain the episcopate, and, if he was made bishop before, he separated himself from the body of those who were, like him, bishops, and from the unity of the Church."
Clearly this doctor of the Church erred. You should submit a petition to Rome to revoke his canonization, which was obviously in error.
You're a sedevacantist?
What manifest heresy has Benedict XVI committed?