Getting his life back (not the life he gave up) is righteousness on God's part.
That needs no explanation... unless you know absolutely nothing about God.
As regards the body, it is nothing but dust.
It served its purpose, and Jesus now has immortal life, in a spirit body, that is imperishable.
Paul explains this in 1 Corinthians 15.
Where in 1Cor 15 does it say that resurrection is as a spirit?
It does say that the body that was sown is raised a spiritual body. So the body that is buried is raised and it is raised as a spiritual body, not as a spirit. (1Cor: 42-44)
The second Adam is a life giving spirit from heaven (He is in us as a Spirit and gives us life) and at the resurrection we bear His image, so our body is a spiritual one, but that does not mean it is a spirit. (1Cor 15:44-49) All we have to do is see what the gospels tell us about the body of the resurrected Jesus to know that.
Flesh and blood is perishable and so this perishable flesh and blood body must put on immortality and clothe itself in the imperishable. (1Cor 15:50-54) But it is our physical body which puts on immortality and imperishability.
Resurrection means that the man who died returns to life,,,,,,,,,,,,gets his life back.
You seem to want Jesus to get another life back. What does that even mean?
Jesus gave His body and life as a ransom for us and got both His life and body back because death could not hold Him (Acts 2:24) because He was sinless. God did not leave Him in the realm of the dead and did not let His body see corruption, how, by raising Him up in His body which had put on immortality and imperishability.
His eternal life is enough to give us eternal life because it never runs out.
The JW idea that the ransom has to be the same as the redemption price is not scriptural, sorry. But of course I digress.