The point you appear to miss with respect to the Catholic Church, is that the Church, herself, is “unchanging”; the fact that the Modernist popes and bishops heretically teach that Church doctrine and dogma must “evolve” is in error. The heresies of the Second Vatican Council were clearly adopted so as to accommodate the Protestant religions in a “spirit of ecumenism”. Nevertheless, simply because many clerics have fallen into heresy does not change one iota of Church doctrine or dogma––all of which is immutable.
But sadly enough, there are many modern Catholics today who would be in complete agreement with your observations. However, those who follow the true teachings of the Catholic Church (“traditional” Catholics), understand that the Modernist popes and prelates have, tragically, been led astray by Satan. We continue to pray for them.
But it has changed...the doctrines of Mary, papal infallibility, etc...all evolved over time.
There is nothing in the NT period about the immaculate conception, assumption, Mary being a co-redemtrix, mediatrix, etc. Those all evolved, incorrectly, over time.
There's even a fifth marian dogma currently evolving. It just doesn't have enough support to be passed yet. Give it time though. It will.