Currently, every function has underneath it its parameters and local variables. I can collapse each function manually, but I have too many to do this, and I have to do it everytime I open VS Code.
You can set the outline to collapse by default by adding "outline.collapseItems": "alwaysCollapse" to your settings.json file [Ctrl + P and search Open User Settings] or by choosing alwaysCollapse in the Outline:Collapse Items dropdown in the settings interface [Ctrl + ,].
You can collapse the outline by clicking on the icon next to the three points or by clicking on an outline element and pressing Ctrl + left key.