You wrote “To my understanding, and I am no expert in this topic, once a person leaves the Church he no longer works within the intent of the Church which is necessary.” You’re saying that leaving the Church means that a minister no longer has the Church’s intent. That reasoning most certainly could apply to baptism as well, since it is necessary to intend to do what the Church does in baptism for validity of the sacrament. Since that is clearly not the case, given that the Church accepts baptisms done outside the Church, provided that their is correct form, valid matter, and proper intent, why would that not also apply to the Eucharist? It is certainly possible for an Anglican minister who was ordained a Catholic priest to intend to do exactly what the Catholic Church does in celebrating the Eucharist, as well as to use correct form and valid matter.
Also, given your reasoning, how is it the case that there are valid sacraments, including Eucharist, among the Eastern Orthodox, Oriental Orthodox, and the Assyrian Church of the East, since they all left the Church in the past? Did their mere act of leaving communion with the Catholic Church amount to an abandonment of doing what the Church does when the Church celebrates the sacraments? Clearly not, since the Catholic Church teaches that all of their sacraments are valid.