Hello Raghu,
I have mentioned the same in your earlier request as well -Embedding Amazon Q on anonymous dashboard
you cannot have build visuals on the top of Dashboard. Dashboards are for readers or consumer, yes reader may ask Q&A on the top of dashboard provided topic is linked to the dashboard when it was published.
Build visuals are executed on Analysis - by user with AuthorPro Role which are priced at 50$/Month and its an assigned user not anonymous users.
Please refer to my earlier post that build visual are done in quicksight console. Console Embedding is possible but topic element still cannot be embed yet. hence, you may to be able to achieve the same via Embedding yet.
Hope this clears your doubt. if you need additional explanation send me a private msg for a possible call.
Cheers,
Deep