Aside from some of the long gaps between text I didn't think it was so bad. And I wholeheartedly approve of a process that checks the preferences of the target audience even if it's not what I (or they) would pick.
However I can't imagine anyone tests well with the video content. The discussion on teachers using AI generated slides (lesson 2) was really interesting, but it had to fight my desire to stop that awful audio. Clearly the sound recording didn't go well and you have what you have, but at least edit it so the three talkers are at some sort of consistent volume. I was raising and lowering trying to make out what was said from one speaker then being deafened by the next.
(To combat the poor sound, and make it more accessible, could be worth looking at adding subtitles. A fun opportunity to play with AI subtitling systems maybe ;) )
Maybe as a concession to us older folks you could make the pagedown key instantly flip to the next page (without changing the position of the current page relative to the viewport)? Then the site could be used like a PDF slide deck in "fit page" mode, which would be a lot better.
I also could not get past my outrage about this, how about a link to the content in a format suitable for the old and cranky? Even raw text would be better than this.
Did you ask an LLM to recommend the most user-friendly UI to you?