Hear me out, So I watched the rings of power and when I saw this seen of him turning into a liquid form. But he uses a bunch of rats and some people to create himself a new body. But he can also shape into what or who ever he wants.
He seems to be made out of mithril. When the rings maker needs more of it, Sauron cuts his hand open and creates a glass full of it. Later on it returns into the black goo it was before. That is why I think Sauron is a makuta
There’s one really big factor keeping RoP Sauron from being considered a Makuta, and that’s the mithril cup. It shapeshifting back into the bootleg Venom sludge proves RoP Sauron can’t be a Makuta by any classification since Makuta cannot control the state of matter separated from them, like the Rahkshi or Kraata. We know this through A: canon and B: Teridax would not have allowed the Turaga to hold the Kraata he and the other Makuta created in the Kraata cave if their state could be manipulated after the fact.
But also bear in mind, Sauron from Rings of Power is a completely different character from Sauron of The Lord of the Rings, as the two share almost nothing in common and the Amazon-owned iteration strays so far from his canonical inspiration that the two become incomparable. It’s hard to name a television show so thoroughly panned by everyone who watched it as Rings of Power has been, and since Sauron has now become the Jared Leto Joker version of Venom, it’s not hard to see why.
No because Tolkien’s lore is not BIONICLE lore.
And also no, because Sauron is not confined to the physical like the Makuta are. They may be made of anti-dermis, but the Makuta still have “programming” and biological components to them. Perhaps this might be considered “spirit” but only so far in BIONICLE, it is all constrained to some semblance of material.
Sauron, in contrast, is not naturally of the flesh, but of spirit. He is Maia, a spirit of Tolkien’s world and the subservient apprentice of Melkor (a much more powerful Valar) before Melkor fell. Sauron may indeed be shapeless, but unlike the Makuta, which do need physical forms via the antidermis to live, Sauron is not so constrained. After he is defeated, he wanders the earth as a spirit trying to regain his power, his soul bound to the ring before it is ultimately destroyed.
uh Chronicler you’re confusing the good LoTR with Amazon’s LoTR
do I have to turn in my man card if I admit I care for neither 
All they had to work with is the appendixes and a billion dollars, it’s 100% their fault it looks like a terrible stage play with bad writing so constricted with the lore!!
Joking aside, yes I am aware of these differences. However 1. I want to point people to the far superior novels and 2. some of this still applies due to “metaphysics” in both franchises and how it’s portrayed.
RoP and BIONICLE seem to be constrained to this idea that the spiritual is not very different from the physical. With RoP, I chalk this up to misunderstanding and ripping apart the lore entirely. In BIONICLE, it’s because magic doesn’t exist, but rather it’s all explained by some sort of energy behind all these crazy powers. BIONICLE uses relativity to explain how things works.
In Middle Earth (and old myth in general, which BIONICLE was disguising it’s lore as), there is a metaphysical. That beyond the material, there is a spiritual, which is far more powerful, and sometimes the spiritual will take the form of flesh, or disguise themselves as flesh.
This is why Makuta cannot be Sauron. Makuta is ultimately constrained to what energy and programming he does have. It is why he is able to properly die when a moon falls on him. Sauron in the books? He is a shapeshifting spirit of evil, able to take different forms and is not bound by the rules of the natural world. Even when the One Ring is destroyed, Sauron’s spirit is not. He merely has severed his connection to the physical, passing back onto the realm of spirit and disappearing from Middle Earth. Makuta? He is dead. Period.
Okay, hear me out: Sauron is MNOG Makuta.
If BIONICLE had actually been about real spirits? Yes.