Add the abillity to symbolize clustered features by the sum of values in an number attirbute. Let the size of the cluster symbol vary with the sum. The label on the cluster and in the table of content should be the sum, not the number of features in the cluster.
In Arcade there's two "fielsd": cluster_count and cluster_avg_ATTRIBUTENAME.
Add a new field: cluster_sum_ATTRIBUTENAME
Here some pictures from Map Viewer (OBS! In Swedish language):
New FieldSymbolsize for cluster