There is no vindictiveness in God’s vengeance… this vengeance was the final outworking of wrath upon the old Mosaic covenant — it had done its job and was past its use-by date and thereafter redundant (Gal 5:23-25; Heb 8:13). God in his great mercy sent many messengers warning of this coming end and thereby in obedience was calling all to guard against it; even to the point of sending His own Son (Mt 21:33-45) who spoke with much clarity as to the coming cataclysm of AD70… as per the mini-apocalypse’ of the gospels.
Nothing of the old covenant régime, bar the consequences of their age-defined blasphemy (Mt 12:32; Mk 3:29) would survive into the coming new age wherein righteousness dwells — which Jesus likewise gave warning of when he predicted… “you will die in your sins” Jn 8:24 — thus not knowing in this life the forgiveness that was theirs, but through stubbornness of heart would pay the price of that coming wrath (Jn 3:18, 36).
For any Hebrew in Palestine and beyond (of which the early church was initially and primarily constituted Acts 2:5; 15:21; 1Pt 1:1) Jerusalem and in particular her Temple was the absolute pinnacle and focal and focus point of their very existence, the epicentre where ‘God’s presence’ dwelt. So… to be potentially shut off or out from the presence of God as they knew it would be death — excommunication or EXILE was death.
So, to recap… “eternal destruction” speaks not to longevity but of TOTALITY — the language is predominately qualitative more than it is quantitative. History bears witness to the fact that in the aftermath of the AD70 conflagrations (the Roman-Jewish wars) a goodly portion of Jewish captives were taken back to Rome and as slaves paraded before the all-conquering and glorious Titus as part of his spoils of war. These captives were all still very much alive, although having had… “their part in the lake of fire” (Rev 21:8) but were now forever banished… permanently exiled (DEATH) away from the presence of the Lord in Jerusalem — their world had come crashing down and they were as dead-men-walking… judged and found wanting.
That in part explains the reality of…
2Thess 1:6-9 …since it is a righteous thing with God to repay with tribulation those who trouble you, and to give you who are troubled rest with us when the Lord Jesus is revealed from heaven with His mighty angels, in flaming fire taking vengeance on those who do not know God, and on those who do not obey the gospel of our Lord Jesus Christ. These shall be punished with everlasting destruction away from the presence of the Lord and from the glory of His power,…
Also… IF you’re concerned about the Greek “away from” of the text, there are a good examples supporting that reading, without taking that further right now; but one thing, in particular, is to be noted… this reading at least mitigates against your concern that said “everlasting destruction” is FROM God, but rather, is the consequence of not heeding God.