Ephesians is such a difficult book.
In context, chapter 2 is talking about the believers at Ephesus having been
(metaphorically) dead in sins, and then
quickened - that is, made to be alive. It is a resurrection of a sort.
Eph 2:1 And you [hath he quickened], who were dead in trespasses and sins; ... 5 Even when we were dead in sins, hath quickened us together with Christ, (by grace ye are saved
The way that the verse declares
ARE SAVED has led many to think of salvation as a single act that happens at a moment in time. That's a MISunderstanding. Here in Ephesians 2, this singular event is only the
beginning of salvation for the Ephesians.
The rest of the book goes on to exhort the Ephesians - now that they have been resurrected - to stay the course, to walk out the path of salvation, and contend for the faith. The book finishes talking about putting on "the full armor of God" and fighting against satan and the powers of this world.
TL;DR - Ephesians 2 is about regeneration, and there's a whole lot that comes after that initial event that is the real focus of the book.