You are perfectly correct in realising this.
There has never been any validity in anyone or any group rejecting what Jesus so carefully instituted and structured – His Catholic Church. No one should settle for less when they come to know His Church. While keeping the priesthood, the Mass and sacraments, the unfortunate result of the eventual breakaway by the Orthodox is that primacy and infallibility can be ignored when it suits – such as with the case of the Orthodox Churches over the infallible teaching against contraception, denial of the Dogma of the Immaculate Conception, and the permission of divorce and remarriage.
**All four promises were made to St Peter alone: **
“You are Peter and on this rock I will build My Church.” (Mt 16:18)
“The gates of hell will not prevail against it.”(Mt 16:18)
“I will give you the keys of the Kingdom of heaven." ( Mt 16:19)
“Whatever you bind on earth will be bound in heaven.” (Mt 16:19) [Later, also to the Twelve].
**St Peter was given supreme authority: **
“Strengthen your brethren.” (Lk 22:32)
“Feed My sheep.”(Jn 21:17).
Then Jesus warned dissenters: “if he refuses to hear even the Church let him be like the heathen and a publican.” (Mt 18:17).
St. Paul says also, “through the Church the manifold wisdom of God might now be made known to the principalities and powers in the heavenly places (Eph 3:10).” The Church teaches even the angels! This is with the authority of Christ!
So at the Council of Chalcedon:
“After the reading of the foregoing epistle [The Tome of Leo], the most reverend bishops cried out: ‘This is the faith of the fathers! This is the faith of the apostles! So we all believe! Thus the orthodox believe! Anathema to him who does not thus believe! Peter has spoken thus through Leo! . . . This is the true faith! Those of us who are orthodox thus believe! This is the faith of the Fathers!’” (Acts of the Council, session 2 [A.D. 451]).
See:
The Papacy
What did the Early Church Fathers Say?americancatholictruthsociety.com/docs/ecfpapacy.htm
It’s interesting also that Sir Arnold Lunn in
Now I See, Sheed & Ward, 1955, could quote from the Anglican Vicar of Oddington, Rev S Herbert Scott, that St Peter and his successors were recognised as the supreme judges in matters of faith by a long succession of great Eastern saints, Ignatius, Irenaeus, Denys, Athanasius, Chrysostom, and others.
The key is that “there is no sure norm outside of the Catholic Church”, because only She teaches with the infallibility conferred by Christ. Confusion and uncertainty come from fallible teaching and picking and choosing.
The Liturgy has been celebrated in an inferior way at certain times and in certain places, since Vatican II (which was not itself responsible for that) but a beautiful Liturgy is available in many places.