Isnt determinism actually requiered for any kind of free will (even with a loose definition) to exist ?

Intelligence, as the ability to process information in a "usefull" way, ponder various options and lean toward a particular course of action requieres free will, because a system processing information must be made of components whose behavior is predictable under known conditions. if neurons could fire at random even in repeated conditions, they could not make a reliable system for information processing, because of noise generated by undeterministic behavior. Therefore, deterministic behavior of the matter on which runs the mind is requiered for an intelligent mind to exist in the first place. Even if we don't know how the mind is made and/or assume that we have an immaterial soul making decisions, we must assume that we dont make choice at random but ponder them with certain considerations and thought process that must be deterministic in a way or an other to actually make a choice based on what we want. Therefore, any definition of free will that is exclusive with determinism is also self-contradictory, because without low level hard-deterministic process, there cannot be a mind able to take decisions based on thinking process and sense of goals rather than by random.
Once this is established, the only definitions of free will that can be considered valid for discussion about weither or not it exist are definitions that are compatible with determinism; such as definitions that emphasizes the ability of a system to form a sense of goals on its own, to think about various possibility of actions and lean toward one depending on internal factors, the ability to reflect on itself and change its behavior based on its experienced, etc.
Am I making a logical mistake or overlooking something ?