Bear in mind that our Lord’s patience means salvation, just as our dear brother Paul also wrote you with the wisdom that God gave him. 16 He 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. 2 Peter 3:15,16
Paul's letters receive a lot of criticism from unbelievers or false teachers because they deal with multiple hot button topics like women's role in the church and home, the rapture, homosexuality, church polity, church discipline, spiritual gifts and more. If you can just say, "Well, that's just Paul's opinion" or "He changes his mind from book to book", then you can read the epistles with a "grain of salt" and not treat them as authoritative. The problem with that is Peter calls them "scriptures" and puts them in the same category as the other scriptures that the early church was using which would eventually become todays Bible - God's inerrant inspired authoritative word given to us by which we get to know Him, hear from Him, and discern His will for our lives.
Peter, himself, admits that some of Paul's writings can be difficult to understand. Note the word "some". That means that most aren't. I once heard a famous Christian quoted as saying, "I'm more concerned with what I do understand about the Bible than what I don't". In other words, there is enough clearly convicting stuff in the Bible to deal with so first get in line with that. Also Peter says "difficult" not "impossible". How deep do you want to dig to understand it? My favorite YouTuber/ Bible Scholar, Mike Winger devoted himself to discovering what Paul's teaching on Women's role in the Church was and once made a 13 hour video on one aspect of this. He desired to understand the difficult and not just say it's impossible.
Lastly, Peter says that if you distort the scriptures you are ignorant and/or unstable and headed for destruction. I see that as two categories - ignorant; untaught, don't know any better and probably don't desire to know. -unstable; like the house built on sand. Choose the easy way to follow the ways of the world. Either way, you will stand before God someday and have to give an account for your disobedience and He will say, "You have no excuse". God has spelled out His will in the Bible and as we have previously mentioned, it butts heads with our wanting to do what we want to do so quite often we look for ways to distort what God is saying so we can fulfill our lusts.
Are you reading the Bible in a submissive way and saying, "God, whatever you say, I will obey"? This is the way.