Hi Cheech,
Thank you for contacting Syncfusion support.
We can get the page size from the existing document by using the property called Size available in the class PDFLoadedPage. Currently, Syncfusion does not have the property to get the PDF orientation, but you can work around this by comparing the actual page width and height.
Refer to the below sample to get the page size and its orientation.
If still you are facing an issue, kindly provide more details such as modified sample, input document, product version to check the issue in our end. So, that it will be helpful for us to analyze and assist you further on this.
Regards,
Gowthamraj K