Hi Mitch,
Thank you for using Syncfusion products.
We have analysed the reported requirement. We would like to
inform you that the chart maintains the aspect ratio and we do not have the
support to change the ratio.
But your requirement can be achieve in new SfChart3D control. Please
refer the below image.

Please let us know if you require further assistance on
this.
Thanks,
Karthikeyan V.