Thank you for contacting Syncfusion support.
We do not have support to “Add HTML content to PowerPoint” and also we do not have immediate plans to implement this feature.
We can also achieve your requirement using the below steps as a workaround:
2. Insert the generated image into the PowerPoint.
We have created a working sample in our end using the above steps, which will be helpful for you to achieve your requirement. Please find the sample from the below link: