Paul is not saying that the man of sin has been revealed at that point. All he is saying at that point is that the day when the Lord comes and we're gathered to Him cannot come until both the apostasy AND the man of sin are revealed first.
Oh, really? Let's look again: I am sure that is what Paul wrote: Here it is in many English translations: I highlighed the "is revealed" so you can easily see it.
AMP Let no one in any way deceive or entrap you, for that day will not come unless the apostasy comes first [that is, the great rebellion, the abandonment of the faith by professed Christians], and the man of lawlessness
is revealed, the son of destruction [the Antichrist, the one who is destined to be destroyed],
AMPC Let no one deceive or beguile you in any way, for that day will not come except the apostasy comes first [unless the predicted great falling away of those who have professed to be Christians has come], and the man of lawlessness (sin)
is revealed, who is the son of doom (of perdition),
CSB Don’t let anyone deceive you in any way. For that day will not come unless the apostasy comes first and the man of lawlessness
is revealed, the man doomed to destruction.
CEB Don’t let anyone deceive you in any way. That day won’t come unless the rebellion comes first and the person who is lawless
is revealed, who is headed for destruction.
DLNT Let no one deceive you in any way, because it will not be present unless the apostasy comes first and the man of lawlessness
is revealed— the son of destruction,
EHV Let no one deceive you in any way, because that day will not come until the falling away comes first, and the man of sin
is revealed—the son of destruction.
ESV Let no one deceive you in any way. For that day will not come, unless the rebellion comes first, and the man of lawlessness
is revealed, the son of destruction,
ESVUK Let no one deceive you in any way. For that day will not come, unless the rebellion comes first, and the man of lawlessness
is revealed, the son of destruction,
GW Don’t let anyone deceive you about this in any way. That day cannot come unless a revolt takes place first, and the man of sin, the man of destruction,
is revealed.
HCSB Don’t let anyone deceive you in any way. For that day will not come unless the apostasy comes first and the man of lawlessness
is revealed, the son of destruction.
ICB Do not let any person fool you in any way. That day of the Lord will not come until the turning away from God happens. And that day will not come until the Man of Evil appears. He belongs to hell.
ISV Do not let anyone deceive you in any way, for it will not come unless the rebellion takes place first and the man of sin, who is destined for destruction,
is revealed.
LEB Do not let anyone deceive you in any way, for that day will not come unless the rebellion comes first, and the man of lawlessness
is revealed, the son of destruction,
MEV Do not let anyone deceive you in any way. For that Day will not come unless a falling away comes first, and the man of sin
is revealed, the son of destruction,
MOUNCE Let no one deceive you in any way; for that day will not come unless the rebellion comes first and the man of lawlessness
is revealed, the son of destruction,
NOG Don’t let anyone deceive you about this in any way. That day cannot come unless a revolt takes place first, and the man of sin, the man of destruction,
is revealed.
NABRE Let no one deceive you in any way. For unless the apostasy comes first and the lawless one
is revealed, the one doomed to perdition,
NASB No one is to deceive you in any way! For it will not come unless the apostasy comes first, and the man of lawlessness
is revealed, the son of destruction,
NET Let no one deceive you in any way. For that day will not arrive until the rebellion comes and the man of lawlessness
is revealed, the son of destruction.
NIV Don’t let anyone deceive you in any way, for that day will not come until the rebellion occurs and the man of lawlessness
is revealed, the man doomed to destruction.
NIVUK Don’t let anyone deceive you in any way, for that day will not come until the rebellion occurs and the man of lawlessness
is revealed, the man doomed to destruction.
NKJV Let no one deceive you by any means; for that Day will not come unless the falling away comes first, and the man of sin
is revealed, the son of perdition,
NLT Don’t be fooled by what they say. For that day will not come until there is a great rebellion against God and the man of lawlessness
is revealed—the one who brings destruction.
NRSV Let no one deceive you in any way; for that day will not come unless the rebellion comes first and the lawless one
is revealed, the one destined for destruction.
NRSVA Let no one deceive you in any way; for that day will not come unless the rebellion comes first and the lawless one
is revealed, the one destined for destruction.
NRSVACE Let no one deceive you in any way; for that day will not come unless the rebellion comes first and the lawless one
is revealed, the one destined for destruction.
NRSVCE Let no one deceive you in any way; for that day will not come unless the rebellion comes first and the lawless one
is revealed, the one destined for destruction.
NTE Don’t let anyone deceive you in any way. You see, it can’t happen unless first the rebellion takes place, and the man of lawlessness, the son of destruction,
is revealed.
RGT Let no one deceive you in any way. For that Day shall not come unless an apostasy comes first and the man of sin
is revealed - the Son of Perdition –
RSV Let no one deceive you in any way; for that day will not come, unless the rebellion comes first, and the man of lawlessness
is revealed, the son of perdition,
RSVCE Let no one deceive you in any way; for that day will not come, unless the rebellion comes first, and the man of lawlessness
is revealed, the son of perdition,
TLV Let no one deceive you in any way, for the Day will not come unless the rebellion comes first and the man of lawlessness
is revealed, the one destined to be destroyed.
WEB Let no one deceive you in any way. For it will not be, unless the rebellion comes first, and the man of sin
is revealed, the son of destruction,
Paul's intent is clear: three times in this passage he said when the restrainer is removed, then the man of sin is or will be revealed.
In verse 3, he wrote as if it had already happened, the restrainer already taken out of the way, and the man of sin already revealed (IS revealed as the above verses show us) - and Paul then shows what He will do and HOW he will be revealed.