Don’t twist Scripture unless you want to be judged by God. Have a look at Romans 8:29 as a starting point, then 10:1 and 11:26 of the very same epistle.
Romans 8:29
For those God foreknew he also predestined to be conformed to the image of his Son, that he might be the firstborn among many brothers and sisters.
I don't see what this has to do with Dispensationalism. More like Calvinistic Predestination.
Romans 10:1
Brothers and sisters, my heart’s desire and prayer to God for the Israelites is that they may be saved.
Paul is hoping that Israelites will be saved (i.e., that they will accept Christ). Why must he hope and pray? Because their salvation is not assured just because they are born Israelites. This passage undermines Dispensationalism.
Romans 11:26
and in this way all Israel will be saved. As it is written: “The deliverer will come from Zion; he will turn godlessness away from Jacob.
Ah, I was waiting for that one.
The Ignatius Catholic Study Bible has an essay on the question: Who Is "All Israel"?
Three theories have been advanced. "All Israel" is...
1. Spiritual Israel (the Church).
2. Ethnic Jews (Dispensationalism).
3. Ethnic Israel (the interpretation of the Catholic essayist).
By "all Israel," Paul means that among the Israelites who accept Christ, there will be members from all 12 tribes.
It does not say how many or few Israelites will be saved. In fact, that prophecy might already have been long fulfilled, as the early Christian communities might well have included members from all 12 tribes.
The essayist observes that many passages in the OT use the phrase "all Israel" to mean the 12 tribes.
Also, Paul was a Benjaminite, a tribe that was almost wiped out in the period of the Judges, something that would have been on Paul's mind.
Judges 21:3
And they said, “O LORD, the God of Israel, why has this happened in Israel, that today there should be one tribe lacking in Israel?”
In Romans 11:26, Paul is assuring his Jewish readers that no tribe will be lacking among those who accept Christ. He is not saying that being born of Jewish blood makes you special, or gives you a special destiny.
Acts 10:34
Then Peter began to speak: “I now realize how true it is that God does not show favoritism.