Just saw your posting - hope not too late to reply.
I use to have a complete help system (html pages) that I would install unzip a archive on first starting on a new device.
But, every-time I wanted to update something, it required a release (was trying to do this without having a dedicated server)
So, with my new release I decided to change things.
Now, I download a file from FirebaseStorage and build a popup menu (I wrote a popup module) and when the user clicks on an entry I download a PDF and show it.
After trying html pages I found that PDF pages resize and show better on all device sizes (just my opinion)
I used to use word to make my html pages now I use word to make pdf pages
All the PDF pages are stored on Firebasestorage and not the users device - makes updating the help easier (could do the same with html pages)
Attaching a screen shot of my App (if you want to see how it looks for real -
my app is free on Google and you can install it and see how it works :
Bowling Brackets
Also attaching the file that gets downloaded when I start and builds the popup menu. Simple stuff
Not sure if any of this helps.