@myunkie The founder Archbishop Lefevbre a Vat 2 Council Father, in which I have respect for, actually signed the first 4 constitutions of the Vatican II. While he never celebrated the N.O. mass, he did offer the interim mass of 1965 to 1969. It was a modified 1962 TLM, in the vernacular with the gloria, credo, and prayers of consecration in Latin. That was the mass that the Council intended.
There are a few problemic areas of the Council but that does not make the Council invalid. A new Council or Pope can issue addendums clarifying and corrections to those areas such as religious liberty, ecumenical, and collegiality.
The Archbishop was the founder of the SSPX but not the founder of the faith held by the SSPX. I am grateful for the wisdom and courage he had, but he always pointed back to the perennial Apostolic Tradition, which is where I place my faith.
The church is not at the point of "fixing the council". The encyclicals and other papal documents since the council have deviated from the Apostolic faith to the point of unmistakable heresy, i.e. direct contradiction of the anathemas of prior councils.
The formulation of the anathemas is interesting. "If anyone says that the rites can be changed or replaced by new ones, let them be anathema." It does not say the Pope cannot change the rites. It says "if he says" they can be changed, he is outside the Church. I am not prepared to assert Paul VI or anyone else was not Pope. That is simply beyond my competence. But the act of creating new rites is precluded because those who suggest it are anathema before they write up the rites for adoption. Notably, Trent also says that those who say that the commandments cannot be kept, with God's grace, are also anathema. Amoris Letitia is based on the "concrete situation" may make keeping the commandments impossible.
The solution to the current decline in the church is to simply apply the pre-existing anathemas.
Not all of Vatican II is problematic. There are some parts that are very orthodox and in continuity with tradition. Bishop Fellay has even said the SSPX accepts 95% of it.
I suspect that neither the founder nor the members of the SSPX would agree with that characterization. It is not the SSPX which has revolted against the Apostolic Faith but clung to it. The rebellion, codified in Vatican II, was against the prior councils to the point of aligning squarely with numerous solemnly pronounced anathemas. We were warned by both Our Lord and Our Lady of false shepherds and heresy among the bishops. Even a coursory examination of the state of the church makes clear who are the rebels and against whom they are rebelling. May God have mercy on their souls.