The questions are really not that hard to understand.
But, apparently, the answers are…
You say that the CC is the only one that can infallibly interpret scripture.
That is exactly what is being said.
I would be interested in know who you say can infallibly interpret scriptures you read. Seriously, just where do you get the idea that 2Tim is the only verse that is necessary in the Bible.
I would like to know what there is about 2Tim. 3:15-17 that you need interpreted?
2Tim tells you about wisdom - and you appear to thinkj that all wisdom is contained in the Bible - but this is not the case. The local library has a catalog of its books - but the catalog does not provide ‘wisdom’ - but, it does tell you (wisely) where to go for the answers! The Bible is one one of the three important elements for the true Christian.
Wisdom tells us to follow Christ and what He said - and Christ said He was founding His Chruch on Peter and his successors. But, you are not doing that.
Wisdom tells us to follow Christ and what He said - and Christ said to eat His Flesh and drink His Blood. But you are not doing that.
Wisdom tells us to follow Christ and what He said - and Christ said to go to his representatives on earth to have our sins forgiven. But, you are not doing that.
Wisdom is more than thinking you have THE ANSWER - Wisdom is doing what is requried with the answer.
So does 2Tim need interpretation YOU BETTER BELIEVBE IT DOES because the view you have presented here is totally contrary with the teachings of Christ - and I just gave you three specific examples above.
And if scripture is able to make us wise unto salvation what more than this is there that you think that we need?
The problem with ‘wisdom’ is that it does not parade around and try to hide its flaws - in fact, we have some real insights from the Bible on this matter:
Proverbs 3:7 Do not be wise in your own eyes…
Proverbs 12:15 The way of a fool seems right to him…
Isaiah 5:21 Woe to those who are wise in their own eyes…
Ultimately, taking one verse and claiming it means something it doesn’t because of personal interpretation is simply foolishness - not wisdom.
The Catholic position seems to be that more is needed outside of what is contained in the bible.
No ‘seems’ about it!

In addition to Sacred Scripture (which even your abridged version of Bible can trace its origin to the Catholic Church) we need Apostolic Tradition and the Magisterium (the teaching authority of the Church - that same authority you revere in Acts 15).
2Tim3:15 says “holy scriptures, which are able to make thee wise unto salvation through faith which is in Christ Jesus.”
Guess what, Richard: you need MORE THAN FAITH. If you doubt this, read the 25 Chapter of Matthew - all of those folks apparently had some kind of faith - but, they did nothing with it! They wound up in hell.
If this is true, what is it that the Catholic Church thinks that we need other than “salvation through faith which is in Christ Jesus.” and the Catholics on this thread keep saying that the CC is the only one that can authoritively interpret scripture. So I would like to know what there is about 2Timothy 3:15-17 that needs interpretation?
Simply stated, people who think this one verse allows them to throw out all of the other verses they do not agree with - well, obviously, there is a REAL NEED for authorative interpretation.
It seems quite clear and straightforward to me. This is about as clear as I can make it pablope.