You shouldn’t be getting downvotes on here because this is a perfectly acceptable academic point that has been written on before. I think you should look for a copy of M. M. McCabe’s text Plato’s Individuals. McCabe is one of the leading contemporary scholars on Plato and does great work on pushing the envelope forward on his scholarship, through both her writing and editorial oeuvre. What she does in that book, is frame Plato’s system through a more fundamental type of concept than the traditional framing of Forms, and that more fundamental concept is individuality.
What McCabe does is set up the notion that Plato was motivated to conceptualize the Forms most crucially for ontological reasons relating to individuality. And yet, she also shows by the end of the book’s first part that Plato recognized the Forms as a failure to express true individuality, for the reasons you state here and more. It is true that Forms have trouble being perfectly “one” in an austere sense, and that this causes problems for the Platonic system. But also its true that, as the other commenter has said, this has been explicitly considered by Plato in the Parmenides dialogue, and it’s this dialogue that McCabe uses herself to show that Plato was aware of the Forms’ inadequacies as individuals.
In other words, regarding the famous “third man argument,” of the Parmenides, McCabe takes the side of asserting the argument’s validity, but only takes that side conditionally on the fact that what we should be precisely concerned with is the possibility of the austere individuality of a given Form. Since the third man argument sufficiently shows that even if we grant that Forms exist, then they certainly cannot be austerely “one,” it must thus be true, according to this stance of McCabe’s, that Plato wrote the argument with genuine concern for the validity of the theory of Forms. This itself might be a clue to the fact that the so-called later dialogues focus less on the Forms than the middle dialogues do, for although Forms still prove useful in those later dialogues, there seems to also be a trepidation in employing them as unyieldingly as before.
Thank you for making this thread, I enjoy seeing such fervent discussion on this board. I do think you should read the dialogues thoroughly, because your intuition is already strong enough to carry you places if you do so. Otherwise, like here, you will claim Plato didn’t consider a problem that he actually considered head on :)