Guru Adi Shankaracharya being a smarta never saw any difference between Shiva and Vishnu. There are many bhasyas of his where he glorifies Shiva as the parabrahman and glorifies Vishnu as well. He rejected both Shaiv and Vaishnav agamas.
Are there any commentaries or quotes of his which he says Aadi parakshakti is the parabrahman or glorifies her?