Labelling and formatting subtotals

Problem/Motivation

Subtotals cannot show any label. Supposedly, the field value of the columns the table is gouped and compressed by would be a standard option. Label set for another column is not shown for subtotals.
Secondly, the sum result does not respect the column format, even without any rewrite applied - see also https://www.drupal.org/project/views_aggregator/issues/3173067 💬 How to format column aggregation totals? Active

Steps to reproduce

Create view for items to be grouped by department, with two currency clumns. Apply group and compress to department columns, and sum to currency columns. Configure for subtotals to be shown.

Proposed resolution

Make totals and subtotal configurable.