The correct translation of 2 thess2:3 is departure/rapture of the church not a falling away from the faith. the KJV is wrong there.
the best scholarship translates it "departure...
See my paraphrase here . My version of 1&2 thess plus the 1st part of John will soon be published somewhere
Two Thessalonians 2
When there is discussion about the meaning of a word, the context of the discussion
reveals the truth….. Here the Thessalonians thought that they had missed the rapture, and Paul assures them they had not..
That is why 2Thess2:3 is properly translated “departure” as in the rapture and not a “Falling Away” as in the KJV.
Here are four early translations of 2Th 2:3…...Tyndale (1534)2Th 2:3 excepte ther come a departynge fyrst— Coverdale (1535)excepte the departynge come first, —–the Geneva Bible (1537)except there come a departing first, —–Cranmer (1539 excepte ther come a departynge fyrst,
2 Thess 2
1..Now we earnestly ask you, our friends, according to the coming of Jesus at the Rapture,
2..That you not be deceived by any letter supposedly from us saying that we had missed the rapture and that the 2nd coming of Jesus is soon.
3...Don’t be deceived for the 2nd coming of Jesus will not come until the departure of the Church in the rapture, followed by the revealing of the anti-Christ
4 This man indwelt by Satan who exalts himself above GOD or is worshipped as god. This man will sit in the newly rebuilt temple showing to himself that he is god
5...Remember that when I was with you, I told you these things?
6...And now you understand that it is the Holy Spirit holds back the coming of the AntiChrist until GODs appointed time
7...For GODlessness in now evident in part until the Holy Spirit ceases from restraining it
8...Then the AntiChrist will be revealed, who is the evil one whom Jesus will devour with his spoken word and with the holy glory of His 2nd coming
9...This AntiChrist who rise to power is through Satanic lying wonders
10...That the unrighteous will be deceived and perish because they refused knowledge of the truth through which they might have been saved