However, for me it is not loaded, probably because you must login to view the video:
You could download the video from TikTok, save it in the Qualtrics library and then just select the video from the library the same way as shown above. You can download by right-clicking the video:
Please think about copyright when using TikTok videos in your survey.
You can also try to embed it as iframe by adding this in the HTML mode (<>):
Since the API does not have any means to explicitly attach media to a question, would using HTML code to embed Graphics / images be the recommended way to create questions with media using the API?