If it wasn't clear to you first time round, I can save you the trouble.
The age of grace is the present age, and it ends at the second advent. The eternal destiny of every human who has ever lived, whether dead or alive, is determined at Jesus' return. There are no exemptions or exceptions, and no further extensions to this period.
The second advent cannot therefore be followed by an earthly kingdom that lasts another 1,000 years, during which there is further opportunity for salvation. Such a concept is a flat contradiction of basic gospel principles, and runs counter to several lines of explicit NT teaching, one of which is represented in the Scriptures quoted above.