I've recently upgraded from Windows 7 Ultimate to Windows 10. I am having what appears to be the exact same issue as the question asked here. My start menu search does not appear to be indexing windows settings; there is always 0 results when I search under the settings category.
I've attempted all of the solutions mentioned in the thread (and anywhere else I could find, for that matter): rebuilding my search index, restarting the search service, and checking
Allow files in this folder to have contents indexed in addition to file properties in
C:\Users\username\AppData\Local\Packages\windows.immersivecontrolpanel_cw5n1h2txyewy\LocalState\Indexed (In my case it was already checked, so I unchecked, applied, checked it again, applied, restarted my computer/explorer/the search service).
This has been very frustrating and I would appreciate any advice short of reinstalling Windows 10.
Here's a screenshot of what my search should index: