Allow fullscreen for embedded YouTube videos in an HTMLViewer?

I’m using a simple HTMLViewer to display a page with an embedded YouTube Video in an app. The Full Screen button doesn’t work and says “Full Screen Unavailable.” Is there any way to allow full screen video from an embedded YouTube video within the app in this situation?

Changing the User-Agent to something iOS worked for me

However it changes the look/layout of the page.

Does the “embed” trick shown on the following post does what you’re looking for?

Thanks for the responses. I’m already using the embed URL, and changing the user agent didn’t seem to change anything. The difference might be that I’m loading a page with embedded YouTube videos instead of showing the actual YouTube website?