By the way, you also wrote:
“The rule of YHWH over the nations through his Son, however, appears not to have been a permanent arrangement. It seems to me that we have to accept that this was a long but ultimately contingent historical phenomenon—Christendom…”
Is that not reading the New Testament backwards rather than forward, as you suggest we should do?
And doesn’t that understanding run counter to what Israel would have understood was promised to them with regard to Messiah, kingdom and his rule over the nations?