You never read a word of Rambam, and yet you’re saying you’ve already got the picture? To be fair, the god most atheists loath (I’m going to assume you don’t) is the Christian one, not the Jewish one. HaShem wasn’t born of a virgin, didn’t die on a cross, nor paid for anyone’s sins. I only say this because you’re dealing with Catholics, you might even be an “ex-Catholic,” therefore, I’m new in this conversation, and, of course, I don’t expect you to know a shred of Judaism since you didn’t grow up Jewish. To give you a slight example of this, there are many midrashim, many aggadot, but do you have to take it all literally? Do demons exist? No. They’re just your shadow, says the Gemara.
Judaism is much like Rick and Morty, earth and space. Whereas Christians believe god came into this world in a three-dimensional form, much like a vase, and at the same time, being the all-powerful Creator, Jews reject this view. Yes, the Creator has unlimited potential and is unbounded by space-time, but we can’t describe it - the Ein Sof. The only way we can describe HaShem is a minute ago, twenty minutes ago, an hour ago, two years ago, all the way back before you were born and think past that and past that and even past that to all creation and even then, past that. Or, go the other way, think of the future. Thirty minutes from now, an hour from now, eternity. It is infinite, boundless. If It did exist in this world as a three-dimensional object, that would mean plurality, that G-d is more than one. But this isn’t Judaism. HaShem is one, in fact, It is the only thing we can truly rely on as being One. Throughout Tanakh and rabbinic commentary, we get this metaphorical descriptions of G-d, but HaShem doesn’t sit in a throne room, It doesn’t have feet, nor does It hear out any subjects, as if It would be in need of that. HaShem doesn’t even need the world, we have nothing to offer G-d. G-d has everything to offer us, out of pure devotion to the Creation. So when G-d hears our prayers, It is lowering Itself towards humanity, to be on our level, as you lower yourself to speak with a child. It cannot run around in the world in flesh, even if It wanted to. Christians say, “Well, G-d can do anything, couldn’t It become human then?” No. G-d doesn’t waste time deciding if It should make a rock too heavy to lift it or not, and It certainty can’t do everything. After all, can G-d be stupid? This would, again, be a waste of time, and G-d doesn’t waste time. Nonetheless, I gave you a mere hint of what G-d is. To find the rest, you have to read your Daf Yomi (Talmud Bavli = Gemara/Mishnah), your daily Torah portion, Yad Hazaka, Moreh Nevukhim, Tosephta, Mekhilta, Sifre, Sifra, Talmud Yerushalmi, and kabbalistic texts. All of Jewish tradition. The whole deal. Only then can you say, with any confidence, that you can speak on HaShem’s behalf as a representative of It, and, therefore, make the claim: “Atheists don’t have depictions of God. We have to rely on the depictions given to us by those who believe in Him.”
Because just reading the Bible alone is never enough.