Question Restatement
What distinctions does "John", (and other New Testament writers), make between the terms, "ζωὴ, (Life)"
and "ψυχὴ, (Soul)"
?
Scope
There are a /lot/ of texts regarding these philosophical concepts. Aristotle, Plato, the Hebrew Scriptures, different authors in the New Testament, etc.
So, this is just about "John" and "other New Testament writers" -- a "Common Denominator", and evidently consistent ...
Answer
The Verse in Question, (John 12:25), is presented last, and actually the conclusion ...
This answer avoids the "contested" properties in order to highlight the "concrete" qualities, affirmed in different contexts.
Life, (ζωὴ) - is a "Property", an Attribute of "Soul":
Rev. 16:3, NASB -
The second angel poured out his bowl into the sea, and it became blood like that of a dead man; and every living thing,[lit. Living Soul, from: ψυχὴ ζωῆς] in the sea died.
Life, (ζωὴ) - is Quantifiable, Can be Increased, Diminished, and Measured:
John 10:10, NASB -
The thief comes only to steal and kill and destroy; I came that they may have life, and have it abundantly.
Just because a "Human Soul" ceases to live / ζωὴ -- they do not become any "less human".
Life, (ζωὴ) - is Subject to the Natural; the Soul is Subject to the Transcendent:
Matt. 10:28, NASB -
Do not fear those who kill the body but are unable to kill the soul; but rather fear Him who is able to destroy both soul and body in hell.
The Soul, (ψυχὴ) - is the Seat of Human Will:
Surrendering the Soul, is the ultimate expression of surrender, not simply dying.
John 12:27 - NASB-
Now My soul, [ψυχή] has become troubled;
Rev. 12:11, NASB -
"And they overcame him because of the blood of the Lamb and because of the word of their testimony, and they did not love their *[life, ψυχὴν -- actually Soul] even when faced with death.
The Soul, (ψυχὴν) - is to be the Focus, and Safeguarded -- "Life" follows Consequently:
John 12:25, NASB -
He who loves his life, [lit. Soul, from ψυχὴν] loses it, and he who hates his life, [lit. Soul, from ψυχὴν] in this world will KEEP, [lit. Guard / Protect, from: φυλάξει] - it, [the Soul] - to life, [from ζωὴν] eternal.
The word "Keep / φυλάξει" - is certainly an ambiguous translation -- but literally denotes "to protect and safeguard"
-- not to "keep or retain".
This is not about "staying alive" -- by avoiding death.
This is about safeguarding the Soul.
According to the texts, by submitting "the Will", (even hating the inclinations of the Soul) -- the Soul can be safeguarded, and thereby enter into eternal life.