Best platform to write a video e-book?

I am not creating an online (video) course. I want to add short videos [4-5 sec long] after every 1-2 paragraph to demo the theory I just taught. There will be ~90 such videos.

I thought of creating an html page with the theory and the videos. Easy to embed a video there.

Do you know any other method to create such an e-book. I plan to sell it on gumroad (only platform to sell e-books, I know of). Hence, the book should only be available to read once you buy it.