Unfortunately, it is not possible to create a dashboard to identify which business transactions/endpoints are performing the most number of SQL queries.
The data is not a simple database metric and is not available to be plotted in a custom dashboard.
However, if you use Java or PHP Application, Database Business Transactions Window in Databases tab shows you business transactions ranked by their cumulative execution time on the database.
You can click each transaction to see the queries run in that particular transaction.