Currently it is not possible to add a date or timeframe dimension to a report in Adobe Target when one doesn't have access to Analytics for Target. See the following forum thread for reference:
https://experienceleaguecommunities.adobe.com/t5/adobe-target-questions/activity-reporting-get-conve...
I'd like to request that it be possible to segment activity reporting by hour, day, week, month, quarter, year, and date. I'm probably missing a level of granularity there.