Well, at first I wanted to use the Treeview Plugin as my main source of navigation, as before Silverbullet I used a directory structure with text files only to categorize my notes.
However later on I realized, that I rather use a combination of tags, filesystem structure and simple searches for navigating.
One reason was, that the Treeview is some kind of “not-so-handy” when using Silverbullet on a smartphone.
I personally endet up just like you wrote: I have a “Main page”, where I list all my “main topics”. But each of my main topics is a subfolder in the filesystem, as well as a own page containing a query which lists all subfolders and all files underneath of “maintopic folder”.
In addition the “main” page has:
- a query, which lists all tags ordered alphabetically.
- direct links to frequently used pages
- my calendar “widget”, where i can access my daily notes pretty quick. (see (Script) Display a calendar for Journal entries - #3 by zeus-web)
- query for last 10 changed files
Hope, it got clear, it is a bit tricky to describe 
This way I have most of my notes just one or two clicks away.
The Treeview is still installed, but I realized, I use it not very often anymore 
One caveat of Silverbullet is, however: Currently I spend more time with Silverbullet itself than with the notes (just like you mentioned with obsidian). But as it is so much fun (for me) to discover all the possibilities it opens through the scriptability (esp. LUA), it is no downside for me for now