You obviously can't understand that the Catholic Church is made up of people that have distorted the Bible and its teachings and do not have the same views of the early Church that was not the Catholic Church.
Do you not see that the introduction of the sacraments into the process of salvation is a creation of works needed to be saved? We can start with the Eucharist, that Christ told us to do in remembrance of Him. John 6 has nothing to do with the Eucharist, so I have no idea why you brought it up. James 5 is very clear that we should confess to each other, and no one doubts that, but to say it is necessary for salvation is in clear contrast to Ephesians 2:8-9. Paul himself talks about Baptism by the Holy Spirit and if Baptism by water was necessary, how then could the thief on the cross next to Jesus have any hope to be with Him in paradise?
What the Bible is clear on, is that belief in Christ is all that is needed for salvation and the Holy Spirit will give you a new heart and new mind to abhor sin and repent.
2 Peter 1:20 says we should interpret prophesy. And I have never claimed that you should interpret scripture by yourself. The need for church elders to help in interpretation is clear. This does not mean that we should no longer read and study ourselves.
2 Timothy 3:16-17 "All scripture is given by inspiration of God, and is profitable for doctrine, for reproof, for correction, for instruction in righteousness: That the man of God may be perfect, thoroughly furnished unto all good works."
In Matthew 16:18-19 is directed solely to Peter. The keys of the kingdom of heaven are not given to him to give to a successor making that successor any more a mediator between God and man than Christ. Jesus is the only mediator as evidenced by the tearing of the veil and opening the Holy of Holies. One can just look at the contradiction of each pope in their doctrine to see that they are just a man making interpretation of scripture.