Yes. We are now slaves to the Christ. Christos Dolous means exactly that.
3 We give thanks to God, the Father of our Lord Jesus Christ, praying always for you, 4 since we heard of your faith in Christ Jesus and the love which you have for all the saints; 5 because of the hope laid up for you in heaven, of which you previously heard in the word of truth, the gospel 6 which has come to you, just as in all the world also it is constantly bearing fruit and increasing, even as it has been doing in you also since the day you heard of it and understood the grace of God in truth;[Colossians 1]
It says the gospel is bearing fruit in all the world. Did everybody who was alive then hear this gospel? No. Those in South America, Central America, North America, Hawaii, Alaska, Guam, North Pole etc. hadn’t heard this gospel at that time. World does not mean everybody whoever lived.
If you were of the world, the world would love its own; but because you are not of the world, but I chose you out of the world, because of this the world hates you.[John 15:19]
Here it says we were chosen out of the world. If world means all whoever lived, how can we be called out of it? World here means the lost, not everybody whoever lived.
He was in the world, and He was in the world, and the world was made through Him, and the world did not know Him, and the world did not know Him.[John 1:10]
He was in the all whoever lived?
And all whoever lived did not know Him?
Again, world rarely means all whoever lived. It say in John 1:10b and the world was made through Him, so here world means all whoever lived because He made everything, including us.