1 John 2:26 These things I have written to you concerning those who are trying to deceive you. 27As for you, the anointing which you received from Him abides in you, and you have no need for anyone to teach you; but as His anointing teaches you about all things, and is true and is not a lie, and just as it has taught you, you abide in Him.
Now please show scripture where it says "doctrine via the Holy Spirit teaching through His Church".
Matthew 28:19-20
Therefore go and make disciples of all nations, baptizing them in the name of the Father and of the Son and of the Holy Spirit, and teaching them to obey everything I have commanded you. And surely I am with you always, to the very end of the age.”
The idea that "you have no need for anyone to teach you" expressed by St. John does not mean that, across the board, nobody needs to teach or be taught. Nor does it mean that everyone is a teacher: that is a particular gift which not everybody has. The office of teaching is clearly very important in the NT Church. And this means more than reciting an appropriate chapter and verse: it means also applying the faith and doctrine of the Apostles to new questions, new controversies, new challenged, in contact with new cultures, which required deeper, wider, or more detailed explanations, and which are arrived at by the Church under the guidance of the Holy Spirit.
All this is par of what we mean when we speak of the "development of doctrine."
The ongoing influence of the Holy Spirit in bringing out new aspects of the truth is clear from the record of the early Church:
Luke 12:12The had the authorization both to rule and to instruct: command and teach:
"...for the Holy Spirit will teach you at that time what you should say.”John 14:26
But the Advocate, the Holy Spirit, whom the Father will send in my name, will teach you all things and will remind you of everything I have said to you.John 15:20
If they obeyed my teaching, they will obey yours also.Acts 2:42
They devoted themselves to the apostles’ teaching and to fellowship, to the breaking of bread and to prayer.Acts 13:1
Now in the church at Antioch there were prophets and teachers: Barnabas, Simeon called Niger, Lucius of Cyrene, Manaen (who had been brought up with Herod the tetrarch) and SaulRomans 12:6-8
We have different gifts, according to the grace given to each of us. If your gift is prophesying, then prophesy in accordance with the faith; if it is serving, then serve; if it is teaching, then teach; if it is to encourage, then give encouragement; if it is giving, then give generously; if it is to lead, do it diligently; if it is to show mercy, do it cheerfully.1 Corinthians 12:28-29
And God has placed in the church first of all apostles, second prophets, third teachers, then miracles, then gifts of healing, of helping, of guidance, and of different kinds of tongues.Are all apostles? Are all prophets? Are all teachers? Do all work miracles?
Ephesians 4:11
So Christ himself gave the apostles, the prophets, the evangelists, the pastors and teachers.
1 Timothy 4:11
Command and teach these things
Teachers were needed:
Acts 8:29-31
The Spirit told Philip, “Go to that chariot and stay near it.”
Then Philip ran up to the chariot and heard the man reading Isaiah the prophet. “Do you understand what you are reading?” Philip asked.
“How can I,” he said, “unless someone explains it to me?” So he invited Philip to come up and sit with him.
Not only Isaiah and the Prophets, but even Apostles like Paul were hard to understand, and needed to be explained correctly:
2 Peter 3:16
[Paul] writes the same way in all his letters, speaking in them of these matters. His letters contain some things that are hard to understand, which ignorant and unstable people distort, as they do the other Scriptures, to their own destruction.
So one can't conclude that nobody needs to teach, that nobody needs to learn from another human being, or that ll are teachers. Neither can one conclude that there will be no development of doctrine, since hte Holy Spirit will (future) "Teach you all things" --- and this means all things, not just what was written down before 100 AD. John said, you remember that if everything Jesus said and did were recorded, the earth itself would not be big enough to hold all the books.
That is NOT to say that there will be new Scriptures or new public revelation. That ceased with the death of the last Apostle. The Canon o Scripture is closed. But the Holy Spirit is teaching His Church the ever wider, deeper ramifications of the Truth that has been handed down to us from the Apostles.