Why aren’t you continuing here? I’m moving the question here:
Maybe I didn’t explain the question correctly. I want to understand exactly how this matter of “a religious court may declare property ownerless” works. How do they have the power to do that without saying that they are uprooting something from the Torah? Granted, if we say that ownership is a social convention, then the bodies that structure society—the religious court—would have the power to revoke ownership. But if we say that ownership exists because of a metaphysical reality, then I don’t understand. If you could shed some light on this, I’d appreciate it. Thanks.

My answer:
I answered that. In your view, how does an act of acquisition revoke ownership and create ownership for someone else? Actions create a change in halakhic metaphysics. A religious court’s declaration of ownerlessness is also an act that creates such a change. I don’t see any problem.

But a transfer of ownership is when I have ownership over an acquisition, so I can make a change in it and apply that change. But how can a religious court do that? Seemingly they have no ownership over the acquisition. And the scriptural derivations mentioned in the Talmud, according to the Rabbi’s approach, are not decrees of the Torah, but rather how the Sages understood ownership—like the Rabbi explains regarding an owner’s despair of recovery.

I don’t understand this discussion. Just as the owner can change ownership, so too the religious court can. It is the representative of the public and can act with regard to any property in its territory.
In any case, this whole discussion has nothing to do with the question of metaphysics and Platonism with which you opened.

So could you explain to me, conceptually, where this power of the religious court over us comes from? Is the fact that it is the representative of the public a power that the public gives it consciously? If the public did not want to give it this power in matters of declaring property ownerless, would it still be able to do so? Thanks.

It does not require the public’s consent.
A religious court receives its power and authority from above (through the chain of ordination). Just as it can establish halakhic directives that obligate the public, it can establish legal directives, declare property ownerless, and so on.

According to Aristotle, is there no distinction between substance and accidents? And if so, would concepts like “tzitzit,” “democracy,” or “a wall”—if certain elements were missing—still not lose their name?

A tricky question. He speaks about objects. As for concepts, if one distinguishes between substance and accident, one returns to Platonism. With concepts one can distinguish between essential and accidental characteristics, but a substance of a concept does not exist. If a concept appears lacking non-essential characteristics, it will not lose its name.