heya! sounds like more of a VtubeStudio setup problem. For hotkeys inside items to run properly you need to first load the item as a normal model to set up the hotkeys with a name(important) and then move it back to the item folder. In the main model that will load the item model, you need to set up a Live2D item action and call that specific hotkey from the item (find it by the model name and by the hotkey name).
Mind you, these hotkeys are limited to mainly expressions and animations. You can always come by our discord server if you have any further questions ♥