You are completely wrong.
First, a real patristic scholar William A Jurgens admitted in volume 3 of faith of the early fathers, that few fathers taught BoD and many outright rejected it.
Even Karl "Anonymous Christian" Rahner has the intellectual honesty to admit this, even if most BoDers don't.
I summarized the evidence on another thread, but the Fathers are overwhelmingly against BoD. We have 5 or 6 Church Fathers who explicitly reject it and only two Fathers who allegedly opined in its favor.
Of the two, St. Augustine admitted it was pure speculation and not received Tradition, saying that he had gone back and forth on the matter and then tentatively stated "I find that ...". At no point did he teach it with any authority. In fact, even as Rahner admits, St. Augustine retracted the opinion, and some of the strongest anti-BoD statements in existence come from his later works.
As for the other, St. Ambrose, who explicitly rejects BoD elsewhere, in his famous Oration at the funeral of Valentinian did NOT teach BoD but merely expressed hope that, like the unbaptized martyrs, those who had this "desire" (zeal, confession) might be "washed but not crowned". Crowning refers to entry into the Kingdom. So this sounds more like a distinction between a type of justification (washing) but not salvation (crowning).
When the question resurfaces after a 700-year silence, in the pre-scholastics, they universally based their opinion (as did Pope Innocent II) incorrectly on the "authority of Augustine and Ambrose". And the other Fathers were chopped liver? Evidently they also did not know that Augustine had retracted his youthful speculation after he had matured his his battles against various heretics, the Donatists and Pelagians, nor did they properly understand St. Ambrose. That's it for their "authority", the house of cards upon which all BoD theory rests.
We have two ways of discerning whether something was revealed (and, therefore, whether the contrary is heretical), namely, 1) unanimous consensus of the Church Fathers, 2) where a doctrine derives implicitly and necessarily from revealed doctrine.
1 is a bit fat negatory as the majority of Church Fathers rejected it, and of the two left, one retracted and the other was misinterpreted
With regard to 2, NO ONE has ever provided any kind of theological proof for BoD. Most never even attempt it. We see only "Augustine and Ambrose", "Augustine and Ambrose", "Augustine and Ambrose".
In the modern theologians, we see only "Yep, BoD.", "Yep, BoD".
Only theologian who even came close to making an attempt to prove it was St. Thomas, but it was not so much proof as explanation. He states that the Sacraments have both a visible and an invisible aspect, and merely states that in BoD you have the invisible without the visible. But not all the graces of all the Sacraments allow the invisible to occur without the visible, and the two which most prominently do not, Holy Orders and Confirmation (there's no such thing as Holy Orders of Desire or Confirmation of Desire), are both, like Baptism, "character" Sacraments that require the visible/physical administration to receive the character. So this isn't any kind of "proof". That one big problem with BoD, its reduction of the character of Baptism to relative meaninglessness, as it's merely some badge of honor that some on Heaven have but others do not.
St. Robert Bellarmine, admitting that the Fathers were divided on BoD, stated that "it would seem too harsh" to say that Catechumens (to whom he limited it) could not be saved this way. Not much of a theological proof there either. It also contradicts his earlier teaching that Catechumens are excluded from the Church due to their non-participation in the Sacraments.