making known to us the mystery of his will, according to his purpose, which he set forth in Christ as a plan for the fullness of time, to unite all things in him, things in heaven and things on earth. (Ephesians 1:9-10)
So God’s will is to unite all things in heaven and on earth under Christ. That is, the angels of heaven and humans on earth will all eventually be under Jesus Christ as supreme ruler. This will be fulfilled in the Kingdom of God after Jesus returns to earth.
God himself is the only being who will not be subject to Jesus as Paul is at pains to point out in his letter to the church in Corinth:
For “God has put all things in subjection under his feet.” But when it says, “all things are put in subjection,” it is plain that he is excepted who put all things in subjection under him. When all things are subjected to him, then the Son himself will also be subjected to him who put all things in subjection under him, that God may be all in all. (1 Cor 15:27-28)