At the moment, Databricks visualizations do not natively support dynamic total rows or grand totals like Excel or Power BI do.
You can show aggregations (SUM, AVG, etc.) in your query, but the visualization layer itself won’t automatically display a “Total” row at the bottom.

If you build dashboards through notebooks or SQL queries, you can use a DataFrame summary and render via display(). Simpler way, it is still sql, use UNION ALL. You can always built a custom visual.

Databricks has this feature on the roadmap for Lakeview Table visualizations, expected to support total and subtotal rows similar to pivot tables soon, but I don't know the release date!