Playing Keynote through HDMI to a TV with iPad

I have a colleague who has a new iPad and a Mac computer. Her Keynote presentations often contain YouTube videos. She can play them on her Mac when connected to a TV and the videos display (picture and sound) as they should. She can play them on her iPad; but, if the iPad is connected to the TV through HDMI the video (picture and sound) don't play. All other slides display on the TV as they should.

I have an iPad Pro (5th gen purchased in 2021). I can play a Keynote presentation and the videos play fine on the connected TV. She can transfer her Keynote to me that won't run the videos on the TV but iPad will using the same HDMI cable and hub connector and TV. We have been unable to find any of our settings that differ.

None of the issues described here seem to outline the same circumstances I have outlined and none of the suggestions we have tried have worked.

My colleague would much prefer using her iPad. It is, of course, much more portable and convenient for her. Any ideas? Any help?