I don’t have verification from the development team, but I don’t think there is a way to make things work with the standard Chromium in the Fedora repos. I can’t test Netflix, but I have issues trying to use Fedora repo Chromium with a Google Chromecast, the casting fails. I have noticed also that if I have Google Chrome installed and Fedora Chromium installed on the same computer, and use Chromium first during that session, then Google Chrome won’t connect to a Chromcast either (probably because of what @grumpey said above in his post). At this time I feel that the best option for Fedora users who want to attempt to use Chromium with Widevine plugins that you try “Chromium-freeworld” first without Chromium installed from the Fedora repos. If that fails to work, uninstall Chromium-freeworld, install Google Chrome and reboot and run Chrome. I know this is not an ideal solution for everyone, but it might be the pragmatic solution that gives you the fuctionality you desire.