•• Jesus states that he is not the One Who is Good in Matt 19:17; Mark 10:10; Luke 18:19. ••
In none of these three reports of the same incident, does Jesus declare that he is not the One Who is good.
Jesus does ask the man why the man, who had called Him ‘good teacher’, is calling Him ‘good’, and affirms that there is One Who is good, God. (A variation of the Shema. Which in Hebrew, though not in Greek, is an affirmation of a compound unity, AeCHaD.) While this could be read as some kind of correction to the man (himself a young religous expert and leader) about Jesus’ own identity, it can also be read as a rabbinic double-meaning tease, leading the man toward acknowledging Jesus as God.
Is there contextual evidence toward this view rather than the other? Yes there is: when the young ruler professes that he has kept the commandments in regard to other people (the so-called second tablet of the ten commandments), Jesus recommends that he should set aside what he loves most (his money) to follow Himself, in order to be complete in following the commandments. But the other commandments (the so-called first tablet) are about following God! Jesus, in all three Synoptic accounts, is making an identification claim with being the God Whom faithful Jews should be following. It would be blasphemously presumptious for any mere human, even a Jewish rabbi (who of all people would be least likely to do this), or even a high-ranking cosmic being, to point toward following himself as a parallel to following God in the ten commandments. (Indeed, any high-ranking cosmic being who tried this, who wasn’t God, would be identifying himself as a Satanic-level rebel instead.)
This objection, consequently, suffers from ignoring the rest of the story being referenced.