I found this post helpful to try and get rid of these items in a non-persistent environment.
[HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Common\TeachingCallouts]
"SLRToggleReplaceTeachingCalloutID"=dword:00000002
"UseTighterSpacingTeachingCallout"=dword:00000002
"CloudSettingsSyncTeachingCallout"=dword:00000002
"Olk_SearchBoxTitleBar_SLR_Sequence"=dword:00000002
"GroupUnreadCountTeachingCallout"=dword:00000002
"MeetingAllowForwardTeachingCallout"=dword:00000002
"AutoSaveFirstSaveWord"=dword:00000002
"ComingSoonTeachingCallout"=dword:00000002
"AutocreateTeachingCallout_MoreLocations"=dword:00000002
"Search.TopResults"=dword:00000002
"DataVisualizerRibbonTeachingCallout"=dword:00000002
"ExportToWordProcessTabTeachingCallout"=dword:00000002
"PreviewPlaceUpdate"=dword:00000002
"RibbonOverflowTeachingCalloutID"=dword:00000002
"PPT_RecordingTab_Callout_Sequence"=dword:00000002
"PowerQueryAsDefaultGetDataTeachingCallout"=dword:00000002
"GroupAdvancedSettingsTeachingCallout"=dword:00000002
"AccCheckerStatusBarTeachingCallout"=dword:00000002
"EnhancedLocationWellTeachingCallout"=dword:00000002
"AutoSaveToggleOnExcel"=dword:00000002
"AutoSaveFirstSaveExcel"=dword:00000002
"a79db66d-e74d-41e8-a138-558044fae3cb"=dword:00000002
"CreatePivotTableFromPowerBITeachingCallout"=dword:00000002
"ThreadedCommentsCallout"=dword:00000002
"Word_CanvasContextual_v3"=dword:00000002
"AutoSaveToggleOnWord"=dword:00000002
"AutoAltText1"=dword:00000002
"SyncProgressUITeachingCalloutA"=dword:00000002
"AutoSaveToggleOnPPT"=dword:00000002
"AutoSaveFirstSavePPT"=dword:00000002
2 more :
VersionHistoryRenameCalloutPPT
TabbedPanesTeachingUI
We are finding more as the days goes on.
If a users gets a new one I just check in the registry what new entry there is and add them to our GPO.
Should be in the Office 16 admx files, but yeah this is the MS way.