I found this online as the Geneva Study Bible.
2 Thessalonians 2 Geneva Study Bible (biblehub.com)
2 Thessalonians 2:3
Let no man deceive you by any means: for that day shall not come, except there come a falling away first, and that man of sin be revealed, the son of perdition;
Let no man deceive you by any means: {3} for that day shall not come, except there come a falling away first, and {e} that man of sin be revealed, the son of perdition;
(3) The apostle foretells that before the coming of the Lord, there will be a throne set up completely contrary to Christ’s glory, in which that wicked man will sit, and transfer all things that appertain to God to himself: and many will fall away from God to him.
(e) By speaking of one, he singles out the person of the tyrannous and persecuting antichrist.
So this seems to emphasize that the falling away is apostasy.
Please be aware I am just sharing what I have discovered so far regarding the Geneva Bible.
This is a description of the Rapture in the KJV.
In the KJV 1 Thessalonians 3:16 - For the Lord himself shall descend from heaven with a shout, with the voice of the archangel, and with the trump of God: and the dead in Christ shall rise first:
17 - Then we which are alive and remain shall be caught up together with them in the clouds to meet the Lord in the air: and so shall we ever be with the Lord.
18 - Wherefore comfort one another with these words.
Paul wrote to Thessalonica and he is reminding them of his ministry to them and encouraging them to continue on in purity and makes the statement of the rapture of the believers while making it clear what happens regarding those who have already died in faith, since they were awaiting the rapture even then.
I am leaning towards 2 Thessalonians 2:3 - meaning what is says, a Falling Away from the true faith, so much so that the AC the lawless one wont’ have a problem finding ready followers when he is allowed to rule.
Since Paul already spoke of the Rapture in his first letter to them, the second letter sounds like it is speaking more about Christs physical return to the earth at the end of the tribulation period. He also speaks about that lawless one.
Have not studied to see if in the early church days, as in Paul’s time, if they had those who were openly of Sodom and Gomorah, and dressed as such, openly leading congregations in buildings called churches and openly mocking God of heaven and earth by declaring they themselves are gods while also encouraging gender confusion and transgender response to that .
I agree that there has always been those who follow a different understanding of the true faith, however, I would question if they were that far removed in their perversions so as to mock everything to do with the truth of the gospel, and even of creation itself the way it is in these end times.
IMO