IMO Paul seems quite clearly to be speaking of a present age(eon), a future age and future ages:
far above all rule and authority and power and dominion, and every name that is named, not only in THIS AGE but also in THE ONE TO COME. (Eph.1:21)
so that in the AGES TO COME He might show the surpassing riches of His grace in kindness toward us in Christ Jesus. (Eph.2:7)
The present age Paul referred to in Ephesians 1:21 is the age of Satan as god:
The god of this age has blinded the minds of unbelievers, so that they cannot see the light of the gospel that displays the glory of Christ, who is the image of God. (2 Cor.4:4)
Clearly Satan is still god so we are still in that age of Satan as god. So the future age & ages Paul referred to above have not yet begun. They won’t begin until Satan is bound & cast into a pit (see Revelation chapter 20) & thereafter (following 1000 more years) cast into the lake of fire where he will be tormented into ages (Rev.20:10). Neither will the future ages Paul referred to begin until the kingdoms of this world become those of Christ (Rev.11:15) who will from that point on reign into the ages. Those ages haven’t started. So there are yet future ages which haven’t even begun.
Other references to multiple future ages:
and He will be King over the House of Jacob for the Ages, and of His Kingdom there will be no end." (Lk.1:33)
And the seventh messenger did sound, and there came great voices in the heaven, saying, ‘The kingdoms of the world did become those of our Lord and of His Christ, and he shall reign into the ages of the ages!’ (Rev.11:15)
and the Devil, who is leading them astray, was cast into the lake of fire and brimstone, where are the beast and the false prophet, and they shall be tormented day and night – into the ages of the ages. (Rev.20:10)
and night shall not be there, and they have no need of a lamp and light of a sun, because the Lord God doth give them light, and they shall reign – into the ages of the ages. (Rev.22:5)
Some introductory historical remarks are required for the next point. The New Testament quotes from the Greek OT much more often than the Hebrew OT. An Old Testament in the Greek language accepted by the early church was known as the translation of Theodotian (see urls below for details).There was also the early Greek OT known as the LXX or Septuagint which has significant differences with the translation of Theodotian.
jewishencyclopedia.com/artic … theodotion
kalvesmaki.com/LXX/NTChart.htm
“Theodotion’s translation of Daniel supplanted the original LXX version which was quite different. The Book of Hebrews (11:33=Daniel 6:23) and Revelation both agree with Theodotion’s translation (Origen’s Hexapla contained these translations).”
bibleandscience.com/bible/so … uagint.htm
“[Theodotian’s] translation, however, is seemingly “quoted” in Heb. 11:33 and several times in Revelations! This strongly suggests that Theodotion’s version was based upon either a lost Greek translation which competed with the LXX or upon a “revised” LXX…Theodotion’s version of Daniel is the one officially accepted by the Church and usually printed in modern editions of the LXX…”
voskrese.info/spl/Xlxx.html
The book of Daniel is closely associated with the book of Revelation which contains our many references to the phrase “the ages of the ages”.
It seems, from the quotes above, that John was more likely to have used a Greek OT in harmony with that of Theodotian’s rather than the LXX.
In Daniel 12:3 this Greek OT of Theodotian, unlike the LXX, speaks of the “eons and further” αἰῶνας καὶ ἔτι]. This is in the context of resurrection spoken of in verse 2, which recalls the resurrections of the book of Revelation. Could Daniel’s reference to “the eons and further” be to a time beyond “the eons of the eons” spoken of in Revelation? Both make reference to eons, but Daniel speaks of what is beyond “the eons”. It seems Daniel may be speaking of a time after that of John’s Revelation references to eons, which would make “the eons of the eons” of a finite duration. If John had wished to convince his readers of the idea of endless eons, readers who may have been familiar with Daniel 12:3, it seems that speaking of mere “eons of the eons” was not the way to do it.
For further reading re God’s Plan of the Eons:
saviourofall.org/Tracts/Eons2.html
martinzender.com/Zenderature/the_eons.htm
heavendwellers.com/hd_eons_and_worlds.htm
da-ath.nl/wp-content/uploads/GPOTE.pdf