Epub larger than a megabyte is very slow to load

[zzyzx-dc]

I have a 20 MB epub which takes several minutes to load on Android.

I can open it in other ereader apps, for instance Myxplorer's ebook reader - and it opens instantly. So I know the epub file is intact.

Additionally, the same exact text in PDF format is 64 MB and Libera opens that file quite rapidly.

I see there are multiple entries for this but I didn't see a resolution. If this is a native issue with how the app handles epub files, perhaps that could be added to the documentation?