The problem is simple. In Plato and Neo-Platonic the ideas are the really real. This world is a reflection of the higher spiritual worlds. So all the multiplicity in this world is really in the Mind [Logos] of God.-- and that creates multiplicity in God.
Understandably this is not acceptable in any approach based on the Torah. The conflict is between Divine simplicity and the reality of the ideas.
The general move of Maimonides and later Jewish thinkers was towards Aristotle that universals and the ideas are real, but depend on particulars. In the Christian world this same problem led to the ideas being considered less and less until we get straightforwards Nomalism [that the ideas don't exist].
Shalom Sharabi (הרש'ש) (in his book Nahar Shalom) developed an approach that is dynamic. His claim is that spiritual reality is itself in a process of change from universals being independent to their being dependent. (This is a problem in itself because the ideas were originally conceived as answering the problem of Parmenides "What is must be and was is not can't be;" so the Ari making change in the world of ideas in itself is already a radical departure from the original concept. so you have to posit higher levels of spiritual world in which there is no change --like the Remak הרמ''ק)
I should probably mention Isaac Luria. It always seemed to me that his major point was simply to put God beyond all processes of creation. In his thought even though Emanation (אצילות) and Adam Kadmon (אדם קדמון א''ק) are Divine, there still come after a long process of contractions and lessening on the Divine light.
To the Ari and the Zohar all lower worlds after emanation are not Divine. And also the Zimzum [contraction] is specifically in God himself the Arizal states many times at the beginning of the Eitz Chaim.
The sad thing is that people that supposedly teach Kabalah are never doing that. They are always teaching some corrupted version of pseudo Kabalah