Hi @CaseyYang-MSFT ,
Thanks for your response.
I was at an impasse where I could only input the value manually. By value, I meant a static value to search for in the query but what I was looking for was a more automatic approach as I wanted to create a Site Page template.
I managed to figure out how to do this. Using PnP Modern Search Results WebPart and the following text query, {|RefinableString00:{Page.WikiCategory}}. It identifies the values in a managed property of the current page and queries pages with the same values of that managed property, WikiCategory.
I created a template Site Page with the WebPart pre-configured so any time a page is created, tagged with a value in the managed property and published it will show automatically all pages that are "related content".
Thanks,
Christian Dias