Problem when using “Highlighted content” modern web part to show document that are linked to certain terms inside our term set

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, 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, where 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 the way i want, where i am facing these issues:-

1. i got this result, which does not show any document:-

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?.