Solved
Not able to search assets based on custom metadata property.
As per https://experienceleague.adobe.com/en/docs/experience-manager-cloud-service/content/assets/manage/search-assets , I am trying to search assets using "GQL search using specific values in metadata fields". But it is not returning results.

property : jcr:content/metadata/dc:dcCode
value: ASC
please help.