en_tn_condensed/isa/07/08.md

the head of Damascus is Rezin

Here "head" is a metonym for the most important part. It is implied that Rezin is only a man, and therefore cannot stop Yahweh's plan. This can be stated explicitly. Alternate translation: "the king of Damascus is Rezin, who is only a man" (See: rc://en/ta/man/translate/figs-metonymy and rc://en/ta/man/translate/figs-explicit)

sixty-five years

"65 years" (See: rc://en/ta/man/translate/translate-numbers)

Ephraim will be shattered and will no longer be a people

Here "Ephraim" refers to all of the northern kingdom of Israel. This can be stated in active form. Alternate translation: "an army will destroy Ephraim, and there will no longer be a people of Israel" (See: rc://en/ta/man/translate/figs-activepassive)