Hello Shaun,
Thank you for the follow-up.
At the moment, there is no supported way to allow iframes inside the Dynamic Content rich text field. The content sanitization process is handled at the framework level to protect the site from potential security risks such as XSS (cross-site scripting), which is why all iframe-based content (including YouTube embeds) is automatically stripped.
Even if Joomla or other editors allow enabling iframe support, in this specific Dynamic Content field the sanitization rules are enforced independently, so it cannot be overridden or disabled from configuration.
Regarding conditional display of media fields, there is also currently no built-in mechanism to render video markup only when a value exists in the field. The video output is tied to the field rendering itself, so when the field is empty, the player container is still generated, which leads to the fallback message you are seeing.
I understand this limitation is not ideal for flexible layouts. I will share your feedback with the development team so they can evaluate possible improvements for conditional rendering and safer embed handling in future updates.
We appreciate your understanding and your input on this—it is valuable for improving the product.