We agree, St Augustine was just a man. By his own words, he was a Catholic ( not sure where you get this “Roman Catholic” from ) Here is the funny part, you call this man who believed in baptismal regeneration, the Real Presence in the Eucharist, The Sacrifice of the Mass, the expanded OT canon, apostolic succession, the papacy, confession, purgatory, prayers to saints, prayers for the dead, infant baptism, one, holy, Catholic, apostolic Church, perpetual virginity of Mary a “Christian” because of one word - predestination. without that, he would be a pagan idolater just like every other Catholic who believes exactly what he believed! another “isn’t it ironic, alena morrisette moment.
I deny Augustine believed in the laundry list you’ve written. Augustine’s own words deny it, particularly his later, more mature work.
Augustine was a Christian; not a “Catholic.”