I've had trouble wrapping my head around that too.
But John tells us that Jesus is the only begotten son.
That only leaves adoption no matter how much I might wish it were not so.
"having been begotten again, not of corruptible seed but incorruptible, through the word of God which lives and abides forever" (1 Peter 1:23)
We were first begotten by our human father and then begotten again by our heavenly Father so that we might be born into an incorruptible body.
"So also is the resurrection of the dead. The body is sown in corruption, it is raised in incorruption. It is sown in dishonor, it is raised in glory. It is sown in weakness, it is raised in power. It is sown a natural body, it is raised a spiritual body." (1 Corinthians 15:42-44)
"For we know that the whole creation groans and labors with
birth pangs together until now." (Romans 8:22)
Birth pangs?
G4944
συνωδίνω
sunōdinō
soon-o-dee'-no
From G4862 and G5605; to have (parturition) pangs in company (concert, simultaneously) with, that is, (figuratively) to sympathize (in expectation of relief from suffering): - travail in pain together.
We can't be born again until we are first begotten again.
Jesus said, "Most assuredly, I say to you, unless one is born again, he cannot see the kingdom of God." (John 3:3)