Hi,
As per our documentation, if you want to target Tablet & ipad users then you should use below keys respectively
d_device_hardware_type contains Tablet
d_device_model contains iPad OR d_device_marketing_name contains iPad
Once you create the Trait you should wait for ~48 hours so that the Trait reporting can be updated.
For more detail information on Device Targeting wth Platform-level keys, please check below documentation on the same
https://experienceleague.adobe.com/docs/audience-manager/user-guide/features/traits/trait-device-tar...
If your issue still persist, then please create a ticket for the same so that someone from AAM team can help because we need furhter details to troubleshoot this concern.
To open a ticket email your issue to amsupport@adobe.com.
Thank You
Prabhat Upadhyay