This is a great question and a common critique. However, I would argue that sin and evil are not necessarily created things in the sense that a substance or object can be a created thing. Like a smartphone or a pint of water.
Rather, if one follows Augustine that moral evil is the absence or perversion of good, then we could also say that sin is the absence or perversion of righteousness. Although it is sometimes dodgy to do theology based on the definition of words, this does seem to capture something of the meaning of sin in Hebrew as ‘missing the mark’ or ‘falling short’. As per Romans 3:23 (NLT), “For everyone has sinned; we all fall short of God’s glorious standard.” (emphasis mine)
For example, murder is a sin because is a corruption of God’s desire that human life is valued and cherished by viewing some lives as less valuable than others. It is also an action devoid of consideration for the victim’s value and worth. In that sense, murder perverts God’s standard of righteousness and as an action lacks the quality of rightness.
However, I wouldn’t say that murder is a ‘thing’ in itself or contains a ‘thing’ called sin or evil. For example, we couldn’t say “can you pass the murder” or “here hold my pint of sin”. This is because, in my view, sin is a descriptive quality of something an action, motivation, or person, is lacking or corrupted.
So, as I see it, evil and sin did not preexist with God, and neither was he the author of sin and evil because sin and evil are conceptual frameworks for describing the absence of a thing, namely righteousness and goodness. And it seems by definition an absence cannot be created.
What do you think?