You both ignore the preposition "in" in the second clause. If "all" means "all" in both clauses, as it does, the "in " means "in" All men are NOT inherently "in Christ"
All mankind are "in Adam" because all mankind are literal descendants of Adam. However, all mankind are not inherently "in Christ."
Being "in Christ" requires an intentional, voluntary action on the part of every person individually.
Romans 3:24 Being justified freely by his grace through the redemption that is
in Christ Jesus:
Not in Christ, no redemption.
Romans 8:1 There is therefore now no condemnation to them which are
in Christ Jesus, who walk not after the flesh, but after the Spirit.
Not in Christ and walk after the flesh, results in condemnation.
2 Corinthians 3:14 But their minds were blinded: for until this day remaineth the same vail untaken away in the reading of the old testament; which
vail is done away
in Christ.
Not in Christ, the veil is not taken away.
2 Corinthians 5:17 Therefore if any man
be in Christ,
he is a new creature: old things are passed away; behold, all things are become new.
Not in Christ, not a new creature, old things are not passed away.
Ephesians 1:10 That in the dispensation of the fulness of times he might gather together in one all things
in Christ, both which are in heaven, and which are on earth;
even in him:
Not in Christ, not gathered together.
Ephesian 2:13 But now in Christ Jesus ye who sometimes were far off are made nigh by the blood of Christ.
Not in Christ, still afar off, not nigh.
2 Timothy 2:10 Therefore I endure all things for the elect's sakes, that they may also obtain the salvation which is
in Christ Jesus with eternal glory.
Not in Christ, do not obtain salvation, no eternal glory.
Paul also said.
1 Corinthians 6:9-10
(9) Or do you not know that wrongdoers will not inherit the kingdom of God? Do not be deceived: Neither the sexually immoral nor idolaters nor adulterers nor men who have sex with men
(10) nor thieves nor the greedy nor drunkards nor slanderers nor swindlers will inherit the kingdom of God.
Galatians 5:19-21
(19) The acts of the flesh are obvious: sexual immorality, impurity and debauchery;
(20) idolatry and witchcraft; hatred, discord, jealousy, fits of rage, selfish ambition, dissensions, factions
(21) and envy; drunkenness, orgies, and the like. I warn you, as I did before, that those who live like this will not inherit the kingdom of God.
Ephesians 5:5
(5) For of this you can be sure: No immoral, impure or greedy person—such a person is an idolater—has any inheritance in the kingdom of Christ and of God.
1 Corinthians 3:17
(17) If anyone destroys God's temple, God will destroy that person; for God's temple is sacred, and you together are that temple.