Hi Scott,
Thank you for reaching out. In the Adwords API there is no dedicated report to be used to retrieve the asset metrics. However, you could try to retrieve the impressions and other metrics by querying the ad_group_ad_asset_view resource in the Google Ads API.
Thanks and regards,
Xiaoming, Google Ads API Team
Hi Scott,
Thank you for reaching out. The RSA and DSA assets are not the types of entities that could be retrieved with metrics by using the ad_group_ad_asset_view. The workaround solution would be to download the metrics from the UI.
Thanks and regards,
Xiaoming, Google Ads API Team