Creating Highlighted Content based on Custom Columns

I'm working with a Sharepoint 365 modern site Home Page. I want to add a new highlighted content section based on the ratings field, which is enabled and set to stars. I thought this would be a simple thing with managed properties, but I cant find the right field..... I even went so far as to create a calculated column based on the ratings field thinking I could access that, but then I noticed none of the custom fields in my document library are showing in the managed property list.

Does anyone out there have the solution? I want a simple web part that shows high rated (starred) documents. Thanks :)