Indeed, I believe that it should read "… or UUIDv7."

    UUIDv1 non-sortable time-based
    UUIDv6 sortable time-based, Gregorian calendar
    UUIDv7 sortable time-based, Unix time
    UUIDv8 sortable time-based, custom time

That is: The custom-time version should only be used if you cannot use one of the standard time versions.