Hi,
Thank you for reaching out, and we apologize for the inconvenience.
Unfortunately, it is not currently possible to embed an <iframe> in the Dynamic Content Rich Text field, as iframe code is filtered out. Additionally, there is no Raw HTML field available within Dynamic Content at this time.
If you would like to add a video to your dynamic content, we recommend using the Video field instead, which is the supported method for displaying videos.
Please let us know if you have any further questions. We'll be happy to assist you.