First - Hashem says not to make images of Him OR the angels. If G-d is concerned about idolatry then why extend the prohibition to other spiritual beings? They also serve Him.
Second - in the Ten Commandments we are told to rest on Shabbos because Hashem does. But the other commandments don't come with a reason. If G-d is G-d and the people are so terrified they tell Moshe they're afraid they will die from hearing Him - why does Hashem bother to give any explanation at all? It could be like the Red Heifer, just an absolute, a given.
I think the two things are connected with the concept of faith.
What is faith in G-d?
It's a form of trust.
It's not the belief that your prayers will be answered; that's obviousy impossible.
Rather it is trust in something unprovable: that there is a Divine Omnipotent.
For Jews, there is an added component. That Hashem created a sort of Tao, energy, set of laws, the Torah, that are the blueprint for an optimally functioning world.
That we received the Torah is a given in terms of our articles of faith. That it tells us what to do is also a given. We may not understand exactly what the commandments are, fundamentally (eg the spiritual mystery of their purpose may never be resolved) but we have faith that they are intentional.
Because the Torah is the way it is - e.g. the Written Law and the Oral Law and the various principles of mesorah (tradition) and interpretation - we will be arguing what the "is" is until Mashiach comes.
We will also be arguing because we are human and lack faith, because we are weak and lazy and prone to evil, and because evil has a way of clinging to good and infiltrating it.
So Hashem knew this in advance of giving us the Torah and baked it in.
"Don't try to make a picture of Me or of the spiritual world, because you are Man and cannot comprehend it, control it or own it like you Men are wont to do."
I imagine G-d "thinking" this. He goes on,
"You must simply have faith that I am here, there and everywhere."
Similarly, when it comes to Shabbos,
"You people have to learn where the action really comes from...Me. If you don't learn to stop all your working on a regular basis, you will not be able to sustain the habit of faith."
But He had to literally tell them - I stop, so you stop - because the urge to lose faith is so strong, especially in dark times.
Of course Hashem is constantly powering the world, yet effortlessly, so even the word "work" is only meant as an approximation for humans to understand.
Why people have trouble believing in G-d is a book or a dissertation. But for me it comes down to personal physical experience, and the need to cognitively mature.
So many times I had hope in people and they betrayed me or let me down. My sense of fairness was destroyed. I feared existentially, for my own survival.
I coped by becoming an overachiever and a workaholic. But that could only last so long.
Now I see that there is no natural cause and effect. There is only trying, and G-d's mercy.
Like my mom always says: "The world doesn't owe you anything."
All opinions my own.