"I do", said the little red hen:
EPH 1:10, “to be put into effect when the times will have reached their fulfillment—to bring all things in heaven and on earth together under one head, even Christ.”
“to be put into effect” refers to God’s mystery
“when the times will have reached their fulfillment” indicates God’s timing
“to bring all things in heaven and on earth together under one head” seems to indicate world unification
“even Christ” names Jesus as the head of God’s government
The mystery Paul has in mind will be explained later in Ephesians in terms of including Gentiles in God’s plan of salvation.
The time of fulfillment would have to be by what is termed the “last days” (in ACTS 2:17, 2TM 3:1 and 2PT 3:3)
or “end of the age” (MT 24:3, 10, 19, 21, etc.).
Other passages indicate that “all things” does not include God’s enemies (1CR 15:25),
who will be separated from those who belong to Christ (1CR 15:23) per the eschatological parables of Jesus
(MT 22:13-14, 24:33, 25:12, 25:30, etc.) and destroyed (1CR 15:26).
Christ’s first advent was for the purpose of creating his spiritual body,
but his second coming will be on Judgment Day (HB 9:26-28)