Omnivore.app is probably the best replacement for Pocket that I've found at the moment, it's open source and has excellent Logseq and Obsidian plugins that allow you to download the articles to your devices.

From there it depends on what kind of reader you're using and software you have on it. Probably the most straightforward would be to use Calibre to convert the markdown file generated by either the Logseq or Obsidian plugins to an epub and add it to your library like a book. KOreader can read markdown files natively if you have it on your device, but you'd have to use a third party sync service to get it on there as there's no plugin for omnivore. It does have a wallabag plugin and a cloud storage plugin (only Dropbox, FTP, and WebDAV are supported) but I haven't tested those.