Col 2:8-15 debunks false means for gaining 'victory' in life -- 5 heresies. Col 2:9 in Christ is the Godhead. Col 2:10 we are complete in Him (Eph 1:23). 5 might works of God are covered. Col 2:11-12 spiritual circumcision and spiritual baptism are illustrations of Christ's victory -- the power of sin is broken; a dead person cannot be tempted.
Paul never met the Colossians but wrote to them from a Roman prison around 62 AD to counter misconceptions of his day. It magnifies the character of Jesus Christ more than any other book in the New Testament, and counters misconceptions of our day as well. The key verse may well be Col 1:18 "...that in all things, He might have preeminence."