I think it is not only one or the other.
But yes each of us has our own development in the New Covenant, but God works each of us with one another and also the whole body of Jesus.
For a sort of an example > yes God wants me to pray and to submit personally to Him. But also He has me praying for various other people, since our Covenant includes how God wants us to pray "for all the saints" (Ephesians 6:18), and "for all men" > 1 Timothy 2:1-4.
So, included in my personal covenant is how others are praying for me while I am caring about others, in prayer.
So, you can't make it totally group or totally individual, I would say . . . not to mention how we are members of one body, of Jesus.
Also, this covenant includes how we are all being changed into the image of Jesus > Romans 8:29. So, then, there are things which go for all of us, though there might be individual details for each person. God is our Creator, He is not a copier. So, yes there is individuality in the mix, like I think you are saying
but also combined relating with God.