Reconciliation means to make friends. Colossians 1:20 is saying that God will bring peace and make friends will all, even satan and the demons provided they are rational creatures. The all here are just as universal as in the verses 16-19. As William Barclay, who I dont up on a pedestal at all, he just happens to be universalist, honest in this context, and famous expert in biblical Greek and Hellenism, said, "We must note that Paul says that in Christ God was reconciling all
things to himself. The Greek is a neuter (panta, Greek
#3956). The point is that the reconciliation of God extends not only to all
persons but to all creation, animate and inanimate." This was also the doctrine of Origen, Clement of Alexandria etc. They got it from the Bible and they did not have the concept of "eternal time" back then, so their biblical letters did not speak of eternal punishment . But before this is a reality, we experience seperation and judgments. The human experience on this earth has lasted over 100.000 years and as the old scholar Milton Terry said, it might last a million more. This is also why Paul elsewhere says Jesus is the saviour of all, (but) especially believers 1 Tim 4v10. One funny example is the socalled prodigal son. The Greek says the son perished. He perished but was later given grace.