God did not give authority to the apostles to determine canon, God determined the canon by inspiring the books which eventually made it into the canon. The church as a whole, not just the apostles, came to recognize the authenticity, the authority, the apostolic origin, and the usefulness of the books that were preserved by the churches.
Again, God determined the canon, the church merely recognized those which were canonical. And that recognition happened slowly over time, as the writings were circulated among the different churches. Some took longer than others, naturally, they were written at different times. Revelation was a late addition because it was written late (95 AD).
If you interchange terms (determine, recognize) it makes the debate pointless.
Yes, Peter accepted Paul's writings because Paul was an apostle Peter was the Apostle to whom the LORD Jesus Christ gave the keys to he kingdom of heaven.
That is the only thing even hinted at in the text.
Peter also pointed out they were difficult to understand.
Yes, and the very next phrase he gives the answer to that problem ... 'which the unlearned/ignorant and unstable/weak torment/twist/distort ... '
What is the solution to understanding those hard things that are in Paul's writings? Don't be unlearned/ignorant ...
What type of learning would be required? Is it not reasonable that one who seeks to understand the hard topics that Paul writes about should at least try to become fluent in the language of the writing? You would certainly go a long way to becoming 'learned' by doing that.
It reminds me of Pauls charge to Timothy that he 'accurately handling the Word of God.' The verb literally means 'interpret correctly' ... Paul told Timothy to work hard at it ...
Good Biblical interpretation of difficult passages doesn't come by assuming a particular theology, it comes by hard work in the Biblical languages, grammar, historical studies, etc. Lucky for us all that there are not very many 'difficult to understand' passages.
Who has the authority to interpret what Paul wrote ? Peter certainly does.
The learned ... that is what Peter said. Peter did not claim authority to interpret what Paul said here ... you are shoe-horning your RC theology into the text.
Your solution has not worked; only genuine apostles/prophets or more likely The Lord's return is going to sort out the mess the nations made of the holy catholic apostolic church.