Below is two verses that tell all three members of the Godhead have been God from eternity
I believe when we have to dig this deep to find an argument--we've gone too far--shot beyond the mark.
The LDS accept God the Son, even Jesus Christ--as their Lord, Savior, and Redeemer--and digging up things man doesn't even understand won't change that. You don't have all the answers--and neither do the LDS. No one does---and we don't need to dig up the whole earth to prove it has soil. That's ridiculous, IMO.
The LDS believe Jesus Christ was the God the Son of the OT--who was the Heir in the NT--and certain things were revealed about Christ, IE--that He received from His God and Father--an inheritance of all things:
Hebrews 1:1-9---King James Version
1 God, who at sundry times and in divers manners spake in time past unto the fathers by the prophets,
2 Hath in these last days spoken unto us by his
Son, whom he hath appointed heir of all things, by whom also he made the worlds;
3 Who being the brightness of his glory, and the express image of his person, and upholding all things by the word of his power, when he had by himself purged our sins, sat down on the right hand of the Majesty on high:
4 Being made so much better than the angels,
as he hath by inheritance obtained a more excellent name than they.
5 For unto which of the angels said he at any time, Thou art my Son, this day have I begotten thee? And again, I will be to him a Father, and he shall be to me a Son?
6 And again, when he bringeth in the firstbegotten into the world, he saith, And let all the angels of God worship him.
7 And of the angels he saith, Who maketh his angels spirits, and his ministers a flame of fire.
8 But unto the Son he saith, Thy throne, O God, is for ever and ever: a sceptre of righteousness is the sceptre of thy kingdom.
9 Thou hast loved righteousness, and hated iniquity;
therefore God, even thy God, hath anointed thee with the oil of gladness above thy fellows.
That means, at some point--God the Son received those things. It also means, if Jesus received those things from His God and Father--then He didn't possess them at some point.
One can make whatever they wish out of that--but there it is. It's something we don't fully understand, and isn't central to our opportunity to inherit eternal life, and would only require an explanation when the critics start down the line you, and the rest of the critics--- pursue here.
Obviously--the author of Hebrews wrote his letter because of questions which permeated the early church--along the lines of your questioning, IMO.
The great majority of the Biblical text centers on what man must do in order to receive God's grace unto life--as a personal reception.
Hebrews 5:9--King James Version
9 And being made perfect, he became the author of
eternal salvation unto all them that obey him;
Which seems to agitate the minds of the critics here.