I moved this to Feature since it feels more like a feature request than a support request. The team is aware that for documentation some other ways to display and order topics is going to be needed, and there are some plans in the works to meet that need. No particular timeline yet for it that I can share, unfortunately.
In the meantime, you may have seen Discourse Doc Categories which allows the creation of a table of contents in the sidebar, as we use here for Documentation.