It seems you have very large (in-memory) dataset. Which premium capacity do you have and how large is your dataset?
This article describes how the Power BI premium service manages resources and provides tips on planning and optimizing your solution.
Additionaly, there is something you may do with my Power BI query / data load to prevent this memory usage.
you can follow those two articles to optimize data model to improve the performance:
If you refresh data in Service, In my opinion, it would be better to refresh the report when the server (which has On-Premises data gateway and data source) is not heavy.