This right here:
Your god has children who will inherit at the end of the race "IF" ... because "Salvation is something one works out in life and something that reaches its fulfillment at the last judgement". Thus at any point between now and the last Judgement, one could fail to 'work out' this salvation and it would, I assume, not reach 'fulfillment'.
What 'working out' does one do in life to reach this 'fulfillment'?
In my world view, salvation is adoption. I had no say or control over my natural birth, I was simply born. Likewise, I am told by scripture that while I was still dead (dead bodies don't do a lot) and an enemy of God (enemies don't do a lot for God) and incapable of saving myself (which makes sense for a dead, enemy of God), GOD did a work. God loved me. God extended His grace and gave me faith. His faith in me, allowed me to "confess with [my] mouth the Lord Jesus and believe in [my] heart that God has raised Him from the dead, [I was] saved. For with the heart one believes unto righteousness, and with the mouth confession is made unto salvation" (Romans 10:9-10). I am already saved.
I am already a member of the household of God:
Ephesians 2:19 Now, therefore, you are no longer strangers and foreigners, but fellow citizens with the saints and members of the household of God, 20 having been built on the foundation of the apostles and prophets, Jesus Christ Himself being the chief cornerstone, 21 in whom the whole building, being fitted together, grows into a holy temple in the Lord, 22 in whom you also are being built together for a dwelling place of God in the Spirit.
1 John 3:1 See what great love the Father has lavished on us, that we should be called children of God! And that is what we are! The reason the world does not know us is that it did not know him. 2 Dear friends, now we are children of God, and what we will be has not yet been made known. But we know that when Christ appears, we shall be like him, for we shall see him as he is. 3 All who have this hope in him purify themselves, just as he is pure.
Since I am already a child of God, I do not NEED to labor to earn my inheritance or to perfect myself. Which is just as well since my best efforts are inadequate to the task. Rather, I can labor in the family business because I am a child of God. Because I am saved. Because I would not wish to bring shame on the family name that I have been given through adoption.