Gen 3:22 And Jehovah God went on to say: “Here the man has become like one of
us in knowing good and bad, and now in order that he may not put his hand out and actually take [fruit] also from the tree of life
+ and eat and live to time indefinite,”
I'm pretty sure we covered this, maybe you didn't see it. Who is the 'us' that is in reference in that scripture? Who is Jehovah speaking to? It is not to the angels, but to his master worker Jesus Christ who created all things. It is the same 'us' when he said 'Let US make man in our image". Whose image, the angels, or our creators?
Your question is, prior to sin, if badness did not exist, how is it that God states that Adam had become like one of
them knowing good and bad?
Certainly, Jehovah's act of creation wasn't spontaneous or impulsive. It wasn't as if one day he casually decided, "Let's create a universe teeming with intelligent beings in my image," and poof, it happened. Instead, just as he teaches within the scriptures, he meticulously planned and calculated every aspect. He set the boundaries, established the standards, and implemented the laws that govern our existence. He created the foundation of time and crafted a spiritual structure upon it, and afterwards he extended it to include the physical creation.
As his creations, we only witness the end results—the completed structure of his creation. We weren't present when he deliberated on what was optimal or perfect. We didn't witness when he determined the speed of light to be 182,282 miles per second or when he defined the parameters of time and space within which we dwell. How could he establish these limits without first testing and determining their standards, calculating his expenditures before constructing?
A standard cannot exist without first defining its boundaries or limits. All the laws governing creation have established thresholds that endure for eternity, unwavering and unbreakable. While Jehovah grants us the ability to manipulate these laws, their fundamental principles remain constants for as long as we creation exists.
Just as we have the ability to imagine and contemplate situations within our own mind, most certainly God had the ability to determine these elements of creation, good and bad, within his own existence prior to creation. Indeed, it's undeniable that
prior to creation, God established these standards based on the thresholds that we see inherent in his creation. Thus, he clearly understands what is detrimental to it, having fashioned everything that exists alongside his only Son—US.