thanks! ArticleFerry already saves a plain EPUB file, so it should work with CrossPoint today: save the article, then on the reader open File Transfer, join your wifi and upload the file from the page it shows (or copy it to the SD card). I haven’t tested it on an X4 myself, so if something renders oddly let me know. sending straight to the reader over wifi would be a neat addition, I’ll note it down.

the affiliate theory sounds right to me, the hijack only pays if every search goes through their tagged link. for locking it down, regular Firefox supports enterprise policies. on Bluefin it’s the system Flatpak, so put a policies.json in /var/lib/flatpak/extension/org.mozilla.firefox.systemconfig/x86_64/stable/policies/ with ExtensionSettings set to "*": {"installation_mode": "blocked"} and "uBlock0@raymondhill.net": {"installation_mode": "force_installed"}. that removes the junk, blocks new installs and he can’t uninstall uBO again. restart Firefox and check about:policies to see it applied.