fixed-layout EPUB question

Hi everyone,
I am teaching a college course with a prescribed curriculum that is based in InDesign.

The final project is to create a digital publication from a print magazine that has a few requirements, most of which are straight forward. However, I am having difficulty with one of the requirements, which is that the fixed-layout EPUB they are designing for a tablet of their choosing be able to switch from the vertical layout to the horizontal layout when the tablet is turned from portrait to landscape.

I tried using liquid layouts and alternate layouts to create the horizontal pages from the vertical pages, and that works pretty well, but when I export it to a fixed-layout eBook file and test it in Apple Books and Adobe Digital Editions, the vertical pages look correct, but the horizontal layouts do not present properly. They cut off at the right side of the vertical page and are pinned to the top with significant whitespace below the design work. In other words, it is showing a vertical page with top left corner of the horizontal design visible. This same set up works for Publish Online, though that doesn't seem to support scrolling text boxes.

If it helps knowing the version I am using, It is the most current cloud version of InDesign v. 18.5. I believe that my students are using the same version or something close to that since they just recently downloaded the cloud version of the app.  Also, I have it on my Mac and PC, and that problem is the same in both versions. 

When I search online for settings or alternative methods for creating InDesign files that rotate to a different orientation when the device is turned, I keep seeing the response that EPUBs don't support alternate layouts.

Is there another way to create a fixed-layout EPUB that supports vertical and horizontal layout orientations in a single file? If so, can you direct me to a resource where I can learn about it?

Alternatively, is there an export setting that I am missing that would allow the device rotation option in an eBook format using the alternate and liquid layouts that I am currently using?

I appreciate any help that I can find for this problem.
Best,
Ari Sutton