The Catholic Church continues to be guided by the Holy Spirit in all truth just as Jesus had promised for His Church.
Do you doubt this promise of the Holy Spirit to guide the Church in all truth?
It goes like this:
Jesus put Peter in charge of the Church and gave all of His authority to him. (Matt. 16:18-19, John 21:17).
The Holy Spirit was given to Peter and the other apostles (John 20:22-23).
But Jesus prayed specifically for Peter (Luke 22:32).
The apostles appointed successors (Acts 1:20)
The Holy Spirit was then passed on from the apostles to their successors by the laying on of hands (Acts 8:18)
Everything in the Bible is the truth. But not all of the truth is contained in the Bible (at least not explicitly).
John 21:25
"But there are also many other things which Jesus did; were every one of them to be written, I suppose that the world itself could not contain the books that would be written."
When Jesus talks about "the seat of Moses", Jesus was making a reference to oral Tradition because the seat of Moses was not written anyplace in the Bible at that time.
Matthew 23:1-3
Then said Jesus to the crowds and to his disciples, "The scribes and the Pharisees sit on Moses' seat; so practice and observe whatever they tell you, but not what they do; for they preach, but do not practice.
And we see in the Bible that "traditions of men" should not be followed but that we should follow the traditions that come from Jesus and were passed down from the apostles and their successors whether by word of mouth or by letter (2 Thess. 2:15, 1 Cor. 11:2)
And the Bible calls the Church, not itself, "the pillar and foundation of truth" (1 Tim. 3:15).
Why does the Bible call the Church and not itself the pillar and foundation of truth? The Bible gives us the answer:
2 Peter 1:20
"First of all you must understand this, that no prophecy of scripture is a matter of one's own interpretation"
The Bible tells us that if we have a disagreement that we should take it to the Church (Matt. 18:17).
It would not make sense to take something to a Church that is invisible. How can you take something to a place if that place can't be found?
So, as we can see from scripture, Jesus intended for His Church to be very visible.
Luke 8:16
No one after lighting a lamp covers it with a vessel, or puts it under a bed, but puts it on a stand, that those who enter may see the light.
Matthew 5:14
"You are the light of the world. A city on a hill can not be hidden.
Vatican City is a city on a hill. Kind of makes you wonder doesn't it?