It would be a great addition to the usability of dashboards if we could filter the layers shown on the map - directly in the dashboard.
I am seeing this when I have a dashboard with three maps (all from the same web map). This map has points and lines.
In one group, I want to show both points and lines, on another group, I want to show just lines, and in the last group, I want to show just points. Currently, if I want to do this, I would have to make three separate web maps, which for the sake of keeping AGOL clean, I do not want to do.
A better solution would be the addition of "visible layers" in the settings for the map element. There, you could turn certain layers on and off per each map element.
I know you can have the option to turn layers on and off in the map, but this refreshes if the page is reloaded.
This solution would be a great way to customize dashboards even more, and create less clutter in AGOL!