I have an idea thanks to my stakeholder: He wanted to see a main metric (by last week, week-to-date and then a spark line), and there should be a button to click on the button, subtotals / different classes that make the total number should be displayed. This can be done except the sparkline/trend display: https://looker.com/platform/blocks/viz/table-with-subtotals
If we can pivot the timeframe and display the trend over time for the subtitles on one tile, it would be amazing.
Upvote for a sparkline visualization in general.