There is an intricate difference when adding an Object in Object Mode or Edit Mode in Blender.  When adding a first Object in Blender, only Object Mode is allowed to add an Object.  Then, if you add another Object in Object Mode, the second Object appears as another Item in the Scene Collection Tree.




Shown below are two Cylinder Objects, each added one in the Layout Workspace and one in the Modeling Workspace, and both under the Object Mode Drop Down Menu.  Notice how two Cylinder Objects appear in the Scene Collection Tree.



If you are in Edit Mode in the Drop Down Menu in Blender, and you continue to Add an Object while in Edit Mode, all the Objects belong to One Tree Item in the Scene Collection Tree.