regarding the scroll bar: Your table has multiple pages, you can still see that there is space needed for the pagination of the table below it, that's why the scrollbar shows up.
Regarding the metrics: We currently don't have an option to just disable the "metric label", but not the value label as you sketched. You can disable legends all together by unchecking the "Show labels" options in the Options tab.
You can also specify a custom label for behind the dash with the "Custom label" options below the metrics aggregation, but not disable it completely.
You could open a feature request on GitHub for this feature.