Please notice, I am able to reproduce the issue as you mentioned. I tried to minimize the plot area but to no avail. I used the following sample code with your template file but the plot area is not changed.
e.g. Sample code:
This is to inform you that your issue has been resolved. The fix will be included in the next official release (Aspose.Cells v22.9) which is scheduled to be released in the second week of September 2022. You will also be notified when the next version is published.
The issues you have found earlier (filed as CELLSJAVA-44812) have been fixed in this update. This message was posted using Bugs notification tool by Peyton.Xu
It works absolutely fine using the newer version. Please make sure you are using Aspose.Cells for Java v22.9. Here is my sample code using your original file:
e.g. Sample code: