The Son of God has a God, which is a Spirit according to John 4:24
John 4:24
King James Version
24 God is a Spirit: and they that worship him must worship him in spirit and in truth.
But his God, is inside of him and the fullness of that Spirit is inside of him. That's what makes him God. The Godhead is the Spirit.
Colossians 2:9
King James Version
9 For in him dwelleth all the fulness of the Godhead bodily.
Hebrews 1:8 Jesus is referred to as God. I hope you watched the video because I really explain everything very easily.
Hebrews 1:8
King James Version
8 But unto the Son he saith, Thy throne, O God, is for ever and ever: a sceptre of righteousness is the sceptre of thy kingdom.
Welcome to the community...CLK
There is a big difference between having something in you and then this something becoming or becomes you as well. This something is still independent from you and you are still you and this something is still it. They are still mutually exclusive and yet can reside together or with each other.
Like the Father (the God and the ONLY head (Godhead/Godhood) of all spirits, the only divine one) is in the Son and the Son is also in us. We are all in union and working ideally as one Spirit, although each of us are still with our own spirits. And yes, as you said in John 4:24, the Father God is Spirit (the creator of all spirits as he is the only source for all of them).
Hebrews 1:8 is an inaccurate translation that has cause confusion and is biased towards or in favor of Trinitarians.
Briefly, it should read with words like "“God is thy throne for ever and ever.” or “God is your throne....” or “God is your throne for ever and ever.”
The Father is saying to his Son that he, his Father is the eternal source and seat of power of righteousness for him and this power of the Father lasts forever. And Yahshua has this power of the Father's throne today. And this power is righteousness and the basis for the Kingdom. Christ holds or upholds the symbol and scepter of righteousness for us in the Kingdom.
It is not saying that the Son has his own independent source of power of righteousness even though his Father gave him immortality. God the Father forbid this could ever be true, and it is not true.
Heb 1:8-14 summary then...
The Son today has the scepter, the rightful means of using the Father's power, of righteousness derived from his Father. The Son never gained righteousness by himself, by his own efforts - or as self-righteousness. It all came from the Father, as our righteousness came from the Father through and because of his Son, in the Kingdom. And the angels will minister to us in the Kingdom, as they do today now and in the future.
APAK