Well, just to clarify, Paul is looking into the future prophetically, when Christ comes as the Deliverer out of Zion at His Second Coming.
In some senses, yes. But as we can both read, the all of Israel who are saved "are" enemies of the Gospel, not "will be enemies" of the Gospel in a future Israel.
Romans 11:
28 As concerning the gospel,
they are enemies for your sakes: but as touching the election, they are beloved for the father's sakes.
Are enemies are NOT a future Israel and that's why reading their salvation as some future tense won't work and has to be ascribed at a minimum to enemies present at the time Paul wrote "are enemies."
Just as they ARE loved, present tense. And would logically extend in reverse to make it ALL Israel saved.
I've also addressed from scripture who is not Israel that is of Israel from Romans 11:8, that being the spirit of slumber that was put upon them all who do not believe. This also ties in directly with the presentations in Mark 4:15, Acts 26:18, 2 Cor. 3:14 and 2 Cor. 4:4 and Eph. 2:2 for a personal kicker.
When that happens all the Jews worldwide (with the exception of some rebels) will be gathered to the land of Israel, and will acknowledge Jesus of Nazareth as their Divine King-Messiah, and be saved. Hence "all Israel shall be saved".
And that is merely you ascribing future tense Israel as the "all" when that is obviously not the case nor can it be the case. All of Israel means ALL of Israel. Every last one of them.
And Israel will be seen as the descendants of Abraham, Isaac, and Jacob, hence belonging to the 12 tribes. The tribe of Dan has been excluded, and Ephraim (called the tribe of Joseph) and Manasseh are treated as two tribes. Why anyone would try to bring Gentiles into the picture is rather bizarre.
Dan is not excluded from Romans 11 "all of Israel." I've already briefly addressed the construct of the tribes earlier in this thread. The figures from Rev. are exactly that. Figures of deeper matters. But I figure you are a more literal tense guy. We're not going to be seeing an external "seal" on the foreheads of Jews at the end. It just ain't going down that way a'tall. It's not a literal matter or a literal number or a literal external seal. None of it is literal, but all of it is quite Spiritually REAL.
Some literalist people think allegories, symbols, figures and parables are not real. They are quite real.
More real than just "literal physical."