sharepoint online – Why is the PnP Search Results web part not sorting library titles?

I am using SharePoint online.
Within a particular site I wanted a page in SitePages to display a sorted list of all the libraries in the site.
I mapped the following Managed Properties as shown at the tenancy level.

As far as I know, it is not possible to initiate a full crawl at the tenancy level.
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I verified that the new values for these managed properties had automatically appeared in the site search schema.
I then re-indexed the site, and waited for an hour or so.
I then added the PnP Search Results web part on the page.

Config Section 1

I set Search query keywords to: *

Config Section 2

I then used the following code to include all libraries, but exclude ‘system’ libraries:

Query Template:

-“Site Pages” -“Form Templates” -“Site Assets” -“Documents” -“Style Library” path:”https://contoso.sharepoint.com/sites/Staff2Student” (contentclass:STS_List_DocumentLibrary)

Edit Sort Order

I did not create any default sort orders here.

Edit Sortable Fields

These are the sortable fields I created:

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The two managed properties then appear in the ‘Sort by’ dropdown, but selection of either has no effect on the sort order of the libraries displayed.
I presume I am missing something obvious here – any thoughts or pointers will be much appreciated!

Thanks in advance,

Jimmy