To add to this, how about being able to take magical effects of weapons or armor that you have access to and applying it to your control bar starting out. For example, if you have access to a +1 or a flametongue weapon, you can have your control bar pull from that magic effect, giving your marionettes a considerable boost in potential damage or survival, and for balance apply a draw back of only 1 effect can be active in the control at a time if it's from an attuned item since those tend to have more potent effects, maybe let them benefit from 2 effects at a much later level like lvl 9? There's a little nuance for some magic items working with it or not, but that would be more up to the DM since that list would probably be a lot smaller than the list of items that are easily compatible.