Modify display depth of the right sidebar

[toastedqu]

Currently, the right sidebar ONLY displays the second headers (i.e., headers that start with ##), with the subheaders collapsed and only visible when you navigate to their corresponding parent section. How can I modify it so that it displays more levels?

My version of JB:

Jupyter-Book v1.0.4.post1
Sphinx v7.4.7
myst v3.0.1
myst-nb v1.2.0
sphinx-multitoc-numbering v0.1.3

Would greatly appreciate some help with this, thanks!