Settings -> Activity Center lets you choose which panels appear in your Activity Center.
Recent Emails does not require a Mail subscription toggle. It requires connected email accounts. If no mail accounts are connected, Kamili One should explain that clearly. When accounts are connected, you can choose which accounts appear and set the maximum number of recent emails. The Recent Emails panel scrolls when there are more records than fit comfortably.
Next Tasks and Next Events are no longer separate Activity Center panels. A Now and Next style panel can be offered when both Calendar and Tasks are enabled. While Calendar or Tasks are feature-flag disabled, the Now and Next option is hidden.
Pinned Tools are hidden until the Toolbox feature flag is enabled.