Not as good as I'd hoped
When I first heard about this app, I had high hopes for it and imagined that I could have a library of files on my NAS which I could access from the app without filling up my iPad (the full Wikipedia is over 100GB). Despite my Mac not having the specifications to use the Kiwix app (requires macOS 12), I can install a browser extension (on Brave) which allows me full access to files stored on my Synology NAS but when I tried to use the Kiwix app on my iPad, it appeared to be downloading the whole file from the NAS to my iPad and apart from filling up my precious iPad space was going to take a long time doing it - I abandoned it but from the rolling numbers looked like a couple of hours at least. So, close but no cigar from me, Kiwix, sorry.