A — Maimonides does not say that if it is sleight of hand then it is permitted; rather, he says one is lashed and not stoned.
And that “deception of the eyes,” according to Maimonides, also means misleading the public: “making it appear that he acted when he did not act” — meaning, here too he is deceiving them.
And of course Maimonides says, “provided he performed an act of sorcery”; could Maimonides, whose language is golden, not have said: “provided he says that he is doing it through sorcery”?

B — Perhaps your intention is that these two distinctions apply in the latter clause: if he says it is sorcery but does it through sleight of hand, it is forbidden and he is lashed; and if he shows that it is sleight of hand, it is permitted. But still, what becomes of the first clause?

https://tora-forum.co.il/threads/%D7%94%D7%90%D7%9D-%D7%99%D7%A9-%D7%9B%D7%99%D7%A9%D7%95%D7%A3-%D7%95%D7%9B%D7%93%D7%95.13216/

In Kesef Mishneh he answered something along the lines of what Michi wrote, and in other ways as well.

Indeed, in the end it’s a nice answer.

According to Maimonides:

Deception of the eyes —
Deception of the eyes is where nothing is actually produced, and at the end of the matter nothing remains. Illusion trick — sawing a person in half. “It appears that he acted, but he did not act”: the person remains whole.

An act of sorcery —
Sorcery is a trick that produces something that remains, such that those who are mistaken will say it was produced by a non-natural power; a stunt like spoon-bending, where the spoon really did bend, but not through magical power, rather by some hidden natural device.

Also in the case of a false prophet, according to Maimonides the intention is a natural trick that the observers did not detect.

After thinking it over, and checking the various magic tricks (I got help from Niv Hadar and his videos),
it doesn’t resolve anything.
Because even metal-bending is either really that nothing bent at all—exactly like sawing a person in half, just sleight of hand, a trick, for example a spoon that was already bent and he just holds it in a way that misleads the audience, and other methods—or there is some hidden hinge in the spoon.
So bottom line, Maimonides really does not fit with the Sages, because the Sages believed in sorcery just as they believed in demons and spirits,
and therefore for them there was a difference between something real and sleight of hand.
It seems simple that Maimonides, on the other hand, could not completely ignore this explicit Jewish law,
but on the other hand he also could not explicitly write that the Sages were mistaken and erred in their mystical beliefs, certainly not in a book that brings every law from the Sages.
And on the other hand there is no concern, because in Maimonides’ time there was already no one who could perform such sorcery anyway, for as the rabbi of Kotzk said, Maimonides by his mystical power (what is called being a Rambamist) decreed and said there are no evil spirits or demons, and they fled.
And the rest—go learn.

But if so, according to Maimonides, about what did the Torah write, “You shall not let a sorceress live”? For according to Maimonides only
“a sorcerer is liable to stoning, provided he performed an act of sorcery,”
which is really the Talmudic statement: “Two gather cucumbers: one gathers and is exempt, and one gathers and is liable; the one who performs an act is liable.”
Meaning, in order to fit with the verse, Maimonides would have to erase the Talmud and say that a sorceress is always liable to death.
And only the Sages, who thought there is a sorcerer who really makes the cucumbers disappear from the field, and one who only makes it appear as though they disappeared, made this distinction.
And Maimonides was not concerned to omit this law the way he omitted several laws about demons, because here there is no practical difference, since there is no Sanhedrin. And as a descendant of Maimonides said, as brought in Kesef Mishneh: “And Rabbi Yehoshua, one of our master’s descendants, answered… and this can only be grasped by one who knows those matters” (he said this on the next difficulty). And people have already pointed out that the Sanhedrin too would presumably need to know this…

Until then, may the earth be filled with knowledge to understand, like Maimonides, that all these things are falsehood and sleight of hand.

And this is of course aside from the other contradiction: six sections earlier, in law 9, Maimonides wrote: “Similarly, one who deceives the eyes and creates the illusion before onlookers that he is doing a wondrous act when he has done nothing—this is included in the category of a soothsayer, and he is lashed.”
Meaning, in section 9, one who deceives the eyes is lashed by Torah law because of soothsaying.
But in law 15, one who deceives the eyes is lashed only rabbinically because of sorcery.
See there for a whole series of attempted resolutions.

Still, it may be possible to explain that even according to Maimonides there is someone who actually gathers something by means of a trick or dexterity—that is, any change in reality brought about by the above, which in people’s eyes is understood as sorcery. Meaning, there really is now a rabbit here, the spoon really bends but there is a hinge; he performed an act of bending the spoon, of producing the rabbit. He performed an act that is indeed only a trick, but in the eyes of the world it is sorcery—that is, it is regarded as having been done by spiritual power—so it is considered sorcery and he is liable. And there is someone who does not actually gather anything, but merely deceives the eyes, like David Copperfield’s making the Statue of Liberty disappear, which is through sleight of hand, sometimes with dexterity too as is known, or spoon-bending in ways that involve no act, such as bringing a pre-bent spoon and merely holding it in a way that is not noticeable, and the like, where it only appears that he did an act. Then it is forbidden only rabbinically; but in any case it is forbidden, since the public still thinks of it as sorcery.

According to what we are saying, it follows that whenever the public knows it is not sorcery, it would be permitted even rabbinically. And indeed, although the halakhic decisors who permitted it when the magician reveals the trick did so only according to the view of those who disagree with Maimonides, according to what we are saying it would be permitted even according to Maimonides. For just as the magician himself may perform for himself or practice with his fellow magician, once the viewers also know, their status is no different from that of the magician himself and his friends. The only question is whether it is enough that he shows this only at the end, or whether he needs to show it from the outset. And it seems obvious that everything depends on what actually happens in people’s minds: if they think he is a sorcerer until he shows them at the end, it is forbidden. But if he announces in advance that it is all a trick and that afterward he will reveal some of it to them, and preferably at the beginning he should even expose one or two tricks, then it is permitted. And what can we do about fools for whom, with every single trick anew, he would need to expose the method? Still, it seems that if he does some trick that really amazes people and it is hard for them to think of a natural explanation, he must make sure there are none of those fools among his audience who will think it is really spiritual power. And truthfully, if there are little children present (also little in understanding), there will always be some like that.

Greetings. Maimonides explains in Sefer HaMitzvot that the act under discussion is mystical ritual worship for idolatry. Meaning, one who deceives the eyes and does no act, but shows before people’s eyes as though he drew his power from some mystical entity—that is what is called “deceiving the eyes.” And one who performs an act of mystical ritual worship is what in his language is called “performing an act.”

https://www.orharambam.com/post/%D7%9C-%D7%90-%D7%99-%D7%9E-%D7%A6-%D7%90-%D7%91-%D7%9A-%D7%95-%D7%9E-%D7%9B-%D7%A9-%D7%A3