The dying of our Lord was to atone for the unbelievers sins.
Once a believer he must now walk worthy of the vocation and continue in the faith or else be cut off with the unbelievers (Romans 11:20-22).
1 John 2:2-4
2 And he is the propitiation for our sins: and not for ours only, but also for the sins of the whole world.
And your mis use of Romans 11 would conradict our predestination which is already saved people to Guaranteed future Adoption / glorification.
9Having made known unto us the mystery of his will, according to his good pleasure which he hath purposed in himself:
10That in the dispensation of the fulness of times he might gather together in one all things in Christ, both which are in heaven, and which are on earth; even in him:
11In whom also we have obtained an inheritance, being predestinated according to the purpose of him who worketh all things after the counsel of his own will:
12That we should be to the praise of his glory, who first trusted in Christ.
13¶In whom ye also trusted, after that ye heard the word of truth, the gospel of your salvation: in whom also after that ye believed, ye were sealed with that holy Spirit of promise,
14Which is the earnest of our inheritance until the redemption of the purchased possession, unto the praise of his glory.( Guarantee future glorification)
eph 4.3030And grieve not the holy Spirit of God, whereby ye are sealed unto the day of redemption. ( Guarenteed future Glorification)
rom 8.23 23And not only they, but ourselves also, which have the firstfruits of the Spirit, even we ourselves groan within ourselves, waiting for the adoption, to wit, the redemption of our body.( Guaranteed future Glorification, not based our our works/ performance/ deeds of faith / tithing / baptism or giving to charity .