With Atlas MongoDB, maintenance windows when not defined default in many cases to periods during peak hours. With maintenance such as automated rolling upgrades, this can impact performance. I would suggest defaulting this to a time overnight relative to the hosted region of the cluster.

In addition, there appears to be no obvious way to see what the maintenance window is without inspecting automated updates in the Activity Feed. If this is the case, adding it to the interface would be useful. Note that even toggling the manual setting of the maintenance window to on will default to the first items in the drop down boxes as opposed to the actual current maintenance window.