How labels be reduced in the legend, yet available to the view when needed?

When using Prometheus and Grafana time-series it seems the Standard Options->Display name could be used with ${__field.labels[“a-label”]} to choose what to show in the legend and tool tip - however there can be excessive information in the legend. Is there a way to show only details in the tooltip? Or is there a way to toggle on an off legend details using Dashboard custom variables such as ( variable ? fields : other_fields ). Even using sum by (label1, label2) makes details inaccessible. How could the user be presented with limited details unless they choose to see all the details?

1.) Create custom dashboard variable labels with multi-value enabled, values: label1,label2,label3
2.) Use it in the panel query aggregation - make sure you have right syntax for used query language, e.g. PromQL: ... by (${labels:csv})
3.) Defined all labels in query legend definition, e.g. {{label1}} {{label2}} {{label3}}

This is idea, not copy&paste solution, which will fit for every use case, so you my need to polish it for your particular use case.