Unable to use the new “Highlighted content” modern web part to show documents that are linked to certain terms inside our term set

Question

I have a document library inside an online classic team site. the document library is linked to a term set using a site column named "Keywords" (internal name = "BibliographyKeywords"), as follow:-

And there is already a managed property created for me, inside the search schema for this site column, as follow:-

Now i want inside a modern page to show the documents (from certain sites) which are linked to certain terms inside the Keywords managed property column. so i find the new modern web part named "Highlighted content", which might help me in achieving this.So i define the following inside the "Highlighted content" web part, as follow:-

1. for the Type i select "Documents"
2. for the Filter and sort, i define the owstaxIdBibliographyKeywords managed property.

Here is screenshot of the "Highlighted content" modern web part settings:-

but i could not get things working, where i am facing these issues:-

1. i got this result, which does not show any document, and not sure what this exactly represents:-

2. second question , which is less important, now inside the document library i have defined a custom content type. but this cusotm content type is not showing inside the Type drop-down list. so does the "Highlighted content" web part's Type list only shows built-in Content types?.

EDIT

I checked my crawl properties, and seems i have 2 crawl properties for the bibliographykeywords column, but seems only one of them is linked to the managed property, as follow:-

also i checked the owstaxIdBibliographyKeywords managed property, and it has the 2 check-boxes "Queryable" & "Retrievable" checked. while the "Searchable" checkbox is uncheck. but on the mapping section of the managed property, i can not find any map to the above crawl property, although as shown above one of the crawl properties are mapped to this managed property. here is the mapping section inside the owstaxIdBibliographyKeywords managed property:-

so can anyone advice on this please?

Answer 1

1) owstaxIdBibliographyKeywords is an automatically generated managed property but is not associated to any crawled property. Secondly, it is not set to Retrieve-able and Query-able. So, it doesnt contain any value in it and hence cant be used in your webpart.

You can find OOTB mulitple managed properties like RefinableString and can edit this Managed property and map it to the crawled property, which will be ows_BibliographyKeywords in your case and then wait for sometime for the crawl to pick up the values. After, that you can use the property like RefinableString10 in your webpart and it will filter values as per your requirement.

2) Yes, it only shows built-in content types and is not customizable since its OOTB webpart. But then in the webpart you can add additional filter using SPContentType as below: