Definition of aion: for ever, an unbroken age, perpetuity of time, eternity, the worlds, universe, period of time, age
Definition of aiōnion: indeterminate as to duration, eternal, everlasting,
God is not the author of confusion. If aiōnion is used by the Holy Spirit to describe eternal life, and the same word used by the Holy Spirit to describe etetnal punishment, I'll go with God's comprehensive clarity.
Blessings
But God had them use the word aion, not eternal. It is translators who chose the word eternal. This is the flaw in the argument. Again, Jesus spoke of the end of the aion. How is something that ends eternal?
39 The enemy that sowed them is the devil; the harvest is the end of the
world; and the reapers are the angels. (Matt. 13:39 KJV)
49 So shall it be at the end of the
world: the angels shall come forth, and sever the wicked from among the just, (Matt. 13:49 KJV)
20 Teaching them to observe all things whatsoever I have commanded you: and, lo, I am with you alway, even unto the end of the
world. Amen. (Matt. 28:20 KJV)
The apostles too spoke of the end of the aion.
3 And as he sat upon the mount of Olives, the disciples came unto him privately, saying, Tell us, when shall these things be? and what shall be the sign of thy coming, and of the end of the
world? (Matt. 24:3 KJV)
You said you'll go with God's comprehensive clarity. Here you go, you have it from the mouth of Jesus.