unidentified missed calls

If the callers have their numbers blocked, you'll see "Unknown Caller". There is nothing you can do on your end to change that.

If you mean you want to know which calls in the Recents list are missed, they are the ones in red. Or you can see only the missed calls by tapping the "Missed" tab at the top of the Recents screen.

If the caller is not among your contacts and/or if that caller isn't using any ID, you can't identify those calls.

They should go to your "Recents" folder (max 100). If you open it, tap on "missed" tab.

Regards

Giulio