In Gen 2:17, some sort of verbal form’s repetition - linked with the meaning of ‘to die’ - must possess a proper and univocal sense (traditionally, this phenomenon is called ‘Infinitive Absolute’).
We have to ask ourselves, The sense of this repetition is related with an emphatical/intensive nuance? Or with an axpect linked with a certainty sense?
Let us proceed step by step.
Young's Literal Translation (and the like): “and of the tree of knowledge of good and evil, thou dost not eat of it, for in the day of thine eating of it - dying thou dost die”.
The Young’s Literal Translation-style translations have no sense, at all.
What means - really - ‘dying thou dost die’? Nothing (in English language).
It is very interesting, as this regard, the passage of 1 King 2:37 ( תמות מות כי תדע ידע). In this verse we found two verbal repetitions, one related to the sense of ‘to know’ (IDO TDO), and the other to the sense of ‘to die’ (MUT TMUT).
Now, let we examine this expression according the various hypothesis.
YLT-style hypothesis: “knowing you will know that dying you will die”. An absolute non-sense, in English language (in Italian, also);
Certainty hypothesis: “you will have to know for sure that you will die, without fail”. A very apt translation.
Now, returning to Gen 2:17, we may repeat the experiment. We have to include also the previous verse (16) because it is contextually linked with the 17.
Not everybody knows the fact that this verse possess two verbal repetition (like 1 Kin 2:37).
In fact, we read (Gen 2:16, 17, I’ve marked the verbal repetition with bold):
Gen 2:16 ויצו יהוה אלהים על־האדם לאמר מכל עץ־הגן אכל תאכל׃
Gen 2:17 ומעץ הדעת טוב ורע לא תאכל ממנו כי ביום אכלך ממנו מות תמות
What is the commonest translation of this paragraph?
KJV:  And the LORD God commanded the man, saying, Of every tree of the garden thou mayest freely eat,  but of the tree of the knowledge of good and evil, thou shalt not eat of it: for in the day that thou eatest thereof thou shalt surely die.
Like you see the KJV-style translation implies two different meaning of the two verbal repetition!
But this is not logical, at all.
If we accept to assign to the first verbal repetition (AKL TAKL) the meaning of ‘mayest freely eat’ I’ve so choose the emphatical/intensive hypothesis. In this case, why - as regards the second verbal repetition (MUT TMUT) - I would skid to the certainty hypothesis, translating “thou shalt surely die”? Where is the coherence?
A given, single, linguistic phenomenon (in this case, the verbal repetition, aka ‘Infinitive Absolute’) ideally matches with a given, single meaning. This is an universal grammar principle (in every language).
So, what meaning is the best meaning we may apply to the phenomenon of the verbal repetition?
The certainty of the verbal-expressed action/condition.
You may ascertain for yourself the correctness of this conclusion examining the following sampling Bible passages (1 Sam 22:16; 1 Kin 2:37, 42; 2 Kin 1:4; Jer 26:8; Eze 3:18, 33; 8:14).
Then, a better translation of Genesis 2:16, 17 (along with my inserted ‘amplifications’) can be:
“IEUE God urged the man, saying: ‘From the whole of the Tree of the protected garden you will eat, beyond all doubt [Adam can’t avoid eating some fruit of the trees. His peculiar bio-physical structure forced him to do so].  Whereas, from the tree of the knowledge concerning good and bad, do not eat from it. For in the period you will eat from it you will die, beyond all doubt [Adam can’t avoid dying after eating the forbidden fruit]’.”