I hope asking a question about Wikipedia is not against the rules, couldn’t find nor confirmation nor contrary in the sidebar.
I have a PocketBook reader that doesn’t support Kiwix. Would need an EPub or another primitive text format. I know a tool to save an archive on epub exists, but no already packed thing with a top 50000/100000 collection.
There is a plugin for calibre ebook software which can generate an epub file from selected wiki articles. Last time I looked it worked fine.