And how do you interpret that line? That every ethnic Jew will be saved due to their DNA? Even the Harvey Weinsteins and Jeffrey Epsteins of the world?
According to the Ignatious Catholic Study Bible, "All Israel" in Romans 11:26 refers to the 12 tribes. Meaning, that among those Jews who accept Christ will be members from all 12 tribes.
Roman 11:26 doesn't indicate whether there will be many or few Jews who, in the end, accept Christ.
Revelation Chapter 7 is the fulfillment of Romans 11:26.