So all things doesn't mean all things?
Scripture does not contain contradictions, so as Jesus says that He lay down His life for the sheep, and tells some hearers that they are
not His sheep, then whatever reconciling all things means, it cannot go against what Jesus said about not dying for everybody without exception. As John Piper writes on this verse:
"Will Everyone Be Saved?
First, through Christ, God reconciles all things to himself, whether in heaven or on earth. Does that mean that there is universal salvation and that, in the end, hell will not exist, and all unbelievers and all demons and Satan himself will be reconciled and saved?
The first problem with that interpretation is that Paul himself, both in this letter of Colossians and elsewhere, teaches that there will be the final wrath of God that will last forever on people. It’s not even that they will be put out of existence (called annihilationism). For example, in
Colossians 3:5–6, he says, “Put to death therefore what is earthly in you: sexual immorality, impurity, passion, evil desire, and covetousness, which is idolatry. On account of these the wrath of God is coming.”
That is only part of the article; the whole can be read here:
How Did God Reconcile ‘All Things’ to Himself?