A metric can be unavailable because the Mac model or macOS does not expose that property to the app.
Disconnected disks, inactive network interfaces, desktop Macs without batteries, sleep, and unsupported hardware naturally omit related readings.
Update diCleaner and macOS, wake the Mac fully, reconnect the relevant device, and reopen Overview.
Permissions can affect some underlying information, but granting every permission does not create unsupported hardware data.
Report the Mac model, macOS version, diCleaner edition, and missing section when a reading should normally be present.