Here are my thoughts, brother.Let me ask.
Knowing that Christ being raised from the dead dieth no more; death hath no more dominion over him. Romans 6:9
And as concerning that he raised him up from the dead, now no more to return to corruption, he said on this wise, I will give you the sure mercies of David. Acts 13:34
Was the Christ, Jesus of a more perfect nature before or after he was raised from the dead? Was he more glorious, before or after the resurrection from the dead?
Is the glory he prayed for in John 17:5 the same glory of 1 Peter 1:21 that states the Father gave to the Son? Is it the same glory of which we as children of God are joint heirs thereof with Christ spoken of in Romans 8:17. Glory we are heirs of, not yet inheritors of. Being we are joint heirs with Christ, when did or has Christ inherited that glory?
Did it require a perfection in nature which he did not have prior to the resurrection. 1 Cor 15:50 Now this I say, brethren, that flesh and blood cannot inherit the kingdom of God; neither doth corruption inherit incorruption. --- Did that verse apply also to Jesus?
Comparing “flesh and blood cannot inherit the kingdom of God” with “nor does the perishable inherit the imperishable.” Paul is speaking of our corruptible bodies now, our flesh and blood, not our resurrected bodies.
I believe that 2 Corinthians 5:11-21 may shed some light on this question. Paul focuses attention to the fact of Christ’s bodily resurrection, but he also explains that this work of God in redemption is God’s act of reconciling through Jesus the world to himself. The difference was not that Jesus gained more glory or greater glory than before. The difference is that humanity being reconciled in Christ gained this glory. In Philippians 2:1-11 Paul teaches that Christ emptied himself and became man, that he was obedient even to the point of death on a cross, and because of this God has exalted him. I think that we can sufficiently hold that Jesus has inherited that glory. I think this consistent with Jesus being the firstborn among many brothers and also being our hope. The answer here comes down to atonement and reconciliation. In other words, Jesus is not somehow more worthy, but there is now "man" in the glory.
Those who are being saved were predestined to be conformed to the image of Christ in order that Jesus may be the firstborn among many brothers. Because of Jesus’ work of redemption, his work of reconciling humanity to himself, we will also be glorified. This is not our own glory, but a glory we have in Christ. But we will also be resurrected and made new. It is not a matter of Jesus having a more perfected nature, but that through his sufferings he perfected our salvation and reconciled man.
Anyway, those are my thoughts on your questions.