You can take action on multiple Insights at once with the Bulk Actions. To enable the selection of Insights, click on the Bulk Actions menu (indicated by the checkbox icon) which will replace the data source icon with a checkbox. Select Insights by checking the relevant boxes or use the 'Select all' option from the floating menu.
Once you have chosen the Insights and selected an action (Acknowledge, Resolve or Delete), you will be presented with a confirmation modal. Within the modal there is an option to also take action any related Insights, which can be used for taking action on more Insights than are visible on the dashboard.
If you wish to resolve every Insight in your account, select all Insights from the bottom floating menu 'Select all' and then tick the checkbox for related insights.
As the Insights dashboard shows only the most recent Insight for each Automation or Anomaly Job, resolving an Insight that has older related Insights will make the next most recent Insight appear.