The term helper said in Shemoneh Esrei is said as a present-tense verb, Hashem (constantly) helps.
מֶלֶךְ עוזֵר וּמושִׁיעַ וּמָגֵן...
King, Helper, and Savior, and Shield...
However, in the Birchos Krias Shema it is said as a noun, Hashem is a Helper.
עֶזְרַת אֲבוֹתֵֽינוּ אַתָּה הוּא מֵעוֹלָם מָגֵן וּמוֹשִֽׁיעַ לִבְנֵיהֶם אַחֲרֵיהֶם בְּכָל־דּוֹר וָדוֹר:
ou have always been the Help of our fathers; a Shield and a Deliverer to their children after them in every generation.
How come the terms for Helper are expressed differently, not so by Shield and Savior?
Perhaps it can be explained based on Shiras Dovid (R' Dovid Goldberg, by Ezras) who says that the passage in Ezras is describing the progression of Hashem's intervention method over the course of time.
At first, Hashem was termed a Helper, because even with man's effort coming with His help, man knew the facts that Hashem was really the Helper fighting and winning the battle.
But over time, man began to think He was in control, Hashem began to be a Savior in order for it to be clear that He is the One in control.
Thus we can say that the passage in Shemoneh Esrei is referring to our current state of Hashem's attribute of Helper, that even when He is helping us, He doesn't manifest in the world anymore as The Helper, but He does nevertheless help, and therefore we user the term that is a verb instead of a noun.
At first, Hashem was termed a Helper, because even with man's effort coming with His help, man knew the facts that Hashem was really the Helper fighting and winning the battle.
But over time, man began to think He was in control, Hashem began to be a Savior in order for it to be clear that He is the One in control.
Thus we can say that the passage in Shemoneh Esrei is referring to our current state of Hashem's attribute of Helper, that even when He is helping us, He doesn't manifest in the world anymore as The Helper, but He does nevertheless help, and therefore we user the term that is a verb instead of a noun.