Download manga from mangalib.me as archived zip.
To install this sctipt you need browser addon such as Tampermonkey https://www.tampermonkey.net/
This script will add new button on title pages at bottom-right with download icon:
Script will save zip archive with folders per chapters and optionally grouped by team and also index.html file as simple manga/manhwa reader with styles and buttons to navigate.
To see progress, you may open console (Ctrl+Shift+I) and watch download logs.
You can find similar userscript for ranobelib.me