Whether you believe Papal Infallibility to be true or not, God willed the Council Fathers to make that decision. This, surely you cannot deny.
This is just more myth-making.
The gathering in 1870AD at the Vatican was a pseudo-council (to borrow a description of it from a well known Melkite Catholic bishop). That pseudo-Council did not decide anything of substance for the church at large, a faction of individuals (now long gone to God) engaged in church-jacking. Not for the first, and possibly not for the last time such a thing would be tried.
So in a sense you are merely their victim, defending the outcome because you think you have no other option.
Marduk is in one way right to say that the Pope has a limited scope of powers, because in Truth he would. The privilege of powers confirmed for the Bishops of Rome at Vatican I are the de facto reality of your church, but not by right or truth.
Your church’s problem, right now, is how to back away of these claims without alarming the faithful, who are not ready to see such a reversal and might not understand that it was all a mistake, undertaken by overzealous bishops at one point in history.
The peoples understanding of church is so bound up with these ideas that moving too rapidly could cause a serious crises in Faith for them. A quick move away from the Papal dogmas could jeopardize their Faith, we must be understanding of this and work slowly to correct the error.
Michael