You are missing the point. What was called "eternal" was in fact only temporary.....
Eighteen examples of the Hebrew “olam” in apposition which shows conclusively it means eternal.
Exodus 3:15
[1](15) And God said moreover unto Moses, Thus shalt thou say unto the children of Israel, The LORD God of your fathers, the God of Abraham, the God of Isaac, and the God of Jacob, hath sent me unto you: this
is my name for ever,[עולם/olam] and this is my memorial unto all generations.
In this vs. “olam” is in apposition, see definition below, to “unto all generations.” “age(s),” a finite period, does not equate to “unto all generations,”“eternal” does.
Psalms 119:44
[2](44) So shall I keep thy law continually for ever [עולם/olam] and ever.[עד/ad]
In this vs. “olam” and “ad” is in apposition to “continually.” “age(s),” a finite period, does not equate to “continually,” “eternal” does.
Psalms 21:4
[3](4) He asked life of thee, and thou gavest it him, even length of days for ever [עולם/olam] and ever.[עד/ad]
In this vs. “olam” is in apposition to “length of days”. “age(s),” a finite period, does not equate to “length of days, “eternal does.
Psalms 45:17
[4](17) I will make thy name to be remembered in all generations: therefore shall the people praise thee [עולם/olam] and ever:[עד/ad]
In this vs. “olam” is in apposition to “all generations,””age(s),” a finite period, does not equate to “all generations”, “eternal” does.
Ezekiel 27:36
[5](36) The merchants among the people shall hiss at thee; thou shalt be a terror, and never shalt be any more. [עד־עולם/ad-olam]
In this vs. “olam” is contrasted with “never shall be”, “age(s),” a finite period, is not the opposite of “never shall be,” “eternal” is.
Ezekiel 28:19
[6](19) All they that know thee among the people shall be astonished at thee: thou shalt be a terror, and never shalt thou be any more. [עד־עולם/ad-olam]
In this vs. “olam” is contrasted with “never shall be”, “age(s),” a finite period, is not the opposite of “never shall be,” “eternal” is.
Psa 33:11
[7](11) The counsel of the LORD standeth for ever, [ עולם] the thoughts of his heart to all generations.
In this vs. “olam” is in apposition to “to all generations,””age(s),” a finite period, does not equate to “to all generations,” “eternal” does.
Psa 146:10 The LORD shall reign for ever, even thy God, O Zion, unto all generations. Praise ye the [8]LORD.
In this vs. “olam” is in apposition to “to all generations,””age(s),” a finite period, does not equate to “to all generations,” “eternal” does.
Psa 37:28
[9](28) For the LORD loveth judgment, and forsaketh not his saints; they are preserved for ever: [ עולם] but the seed of the wicked shall be cut off.
even thy God, O Zion, unto all generations. Praise ye the LORD.
In this vs. “olam” is in apposition to “unto all generations,””age(s),” a finite period, does not equate to “unto all generations,” “eternal” does.
[10]Ecc 3:14
(14) I know that, whatsoever God doeth, it shall be for ever: [ עולם] nothing can be put to it, nor any thing taken from it: and God doeth it, that men should fear before him.
In this vs. nothing can be added or taken away from God’s acts. “age(s),“ a finite period, does not equate to “nothing can be added or taken away from God acts” “eternal” does.
Isa 51:6
[11](6) Lift up your eyes to the heavens, and look upon the earth beneath: for the heavens shall vanish away like smoke, and the earth shall wax old like a garment, and they that dwell therein shall die in like manner: but my salvation shall be for ever, [ עולם] and my righteousness shall not be abolished.
In this vs. “olam” is in apposition to “shall not be abolished”, “age(s),” a finite period, does not equate to “shall not be abolished,” “eternal” does.
Isa 51:8
[12](8) For the moth shall eat them up like a garment, and the worm shall eat them like wool: but my righteousness shall be for ever, [ עולם] and my salvation from generation to generation.
In this vs. “olam” is in apposition to “generation to generation,”age(s),” a finite period, does not equate to “generation to generation,” “eternal” does.
[13]Dan 4:34
(34) And at the end of the days I Nebuchadnezzar lifted up mine eyes unto heaven, and mine understanding returned unto me, and I blessed the most High, and I praised and honoured him that liveth for ever, whose dominion is an everlasting [ עולם] dominion, and his kingdom is from generation to generation:
In this vs. “olam” is in apposition to “from generation to generation,”age(s),” a finite period, does not equate to “from generation to generation,” “eternal” does.
Dan 4:3
[14](3) How great are his signs, how mighty his wonders! His kingdom is an eternal [ עולם] kingdom; his dominion endures from generation to generation.
In this vs. “olam” is in apposition to “from generation to generation,”age(s),” does not equate to “from generation to generation,” “eternal” does.
Dan 7:14
[15](14) He was given authority, glory and sovereign power; all nations and peoples of every language worshiped him. His dominion is an everlasting [ עולם] dominion that will not pass away, and his kingdom is one that will never be destroyed.
In this vs. “olam” is in apposition to “will not pass away” and “never be destroyed,” “age(s),” a finite period, does not equate to “will not pass away, never be destroyed”, “eternal” does.
Jer 23:40
[16](40) I will bring on you everlasting disgrace [ עולם] —everlasting shame [ עולם] that will not be forgotten."
In this vs. “olam” is in apposition to “will not be forgotten,” “age(s),” a finite period, does not equate to “will not be forgotten,””eternal” does.
Jer 50:5
[17](5) They will ask the way to Zion and turn their faces toward it. They will come and bind themselves to the LORD in an everlasting [ עולם] covenant that will not be forgotten.
In this vs. “olam” is in apposition to “will not be forgotten,””age(s),” a finite period, does not equate to “will not be forgotten,” ”eternal” does.
Hab 1:12
[18](12) LORD, are you not from everlasting? [ עולם] My God, my Holy One, you will never die. You, LORD, have appointed them to execute judgment; you, my Rock, have ordained them to punish.
In this vs. “olam” is in apposition to “will never die,””age(s),” a finite period, does not equate to “will never die,” ”eternal” does.
Here are four examples of the Hebrew “ad” in apposition which show conclusively that it means “eternal.”
Psa 21:4
[1](4) He asked life of thee, and thou gavest it him, even length of days for ever and ever [עד/ad]
In this vs. “ad” is in apposition to “length of days.” “age(s),” a finite period, does not equate to “length of days,” “eternal” does.
Psa 119:44
[2](44) So shall I keep thy law continually for ever and ever.[עד/ad]
In this vs. “ad” is in apposition with “continually.” “age(s)” does not equate to “continually” “eternal” does.
Psa 45:17
[3](17) I will make thy name to be remembered in all generations: therefore shall the people praise thee for ever and ever.[עד/ad]
In this vs. “ad” is in apposition with “in all generations.” “Age(s)” does not equate to “all generations”
Pro 12:19
[4](19) The lip of truth shall be established for ever: [עד/ad] but a lying tongue is but for a moment.
In this vs. “ad” is contrasted with ”for a moment.” “Age(s)” is not opposite to “for a moment” “eternal” is.
The definition of “apposition” from a Hebrew grammar.
§131. Apposition.
131
a 1. Apposition in the stricter sense is the collocation of two substantives in the same case in order to define more exactly (or to complete) the one by the other, and, as a rule (see, however, below, under g), the former by the latter. Apposition in Hebrew (as in the other Semitic languages[1]) is by no means confined to those cases in which it is used in English or in the classical languages. It is not infrequently found when either the subordination of one substantive to the other or some more circumstantial kind of epexegetical addition would be expected.
https://en.wikisource.org/wiki/Gesenius%27_Hebrew_Grammar/131._Apposition
How do I explain your examples? Hyperbole! In your examples olam is not defined or described by other adjectives/adjectival phrases as a period shorter than eternal, as in the verses I quoted.
Here is a verse where God clearly uses hyperbole.
Ezekiel 32:3-6
3 Thus saith the Lord GOD; I will therefore spread out my net over thee with a company of many people; and they shall bring thee up in my net.
4 Then will I leave thee upon the land, I will cast thee forth upon the open field, and will cause all the fowls of the heaven to remain upon thee, and I will fill the beasts of the whole earth with thee.
5 And I will lay thy flesh upon the mountains, and fill the valleys with thy height.
6 I will also water with thy blood the land wherein thou swimmest, even to the mountains; and the rivers shall be full of thee.