You can try to stick the tree to the hitbox instead of the other way around, and separate the hitboxes away from each others, since the hitbox is only half the size of the tree (similar to the size of the trunk).
You need to separate hitboxes from each others not the the trees (last action).
Also did you try to place the “stick trees to hitbox” in the same event after you create the objects? You don’t need to check for nearest object to stick them, but I’m not sure if you already tried it and it doesn’t work after creating two objects at the same time.
I’m at work rn so unfortunately not.
But I also figured out that for some reason the draggable behaviour works for the trees but not for the hitboxes. When I’m back from work I will try to create a new hotbox object and try it with that