We have built a process to collect damage data in Survey123 using a hosted feature services connected to our SDE. Every half hour data is processed to determine county totals and a separate feature class is updated. Our dashboard is using that feature class to display a map with damage points, gauges showing if each county's FEMA threshold has been reached, and serial charts indicating FEMA and FHWA totals.
When the refresh occurs I can see the map lose its points while the feature class is being emptied and repopulated. Some of the gauges and one chart indicate updates every few seconds. However other similar items are not being refreshed.
According to documentation I can find, dashboard items are updated every time there's a change.