I doubt they could get away with banning plex due to its integrated ad-supported streaming service which there are likely a few users of. But for jellyfin that same argument wouldn’t work. At least initially I suspect no self-hosted content would be blocked, as there are plenty of apps/viruses out there openly created solely for the purpose of piracy. Jellyfin isn’t the same as these as it doesn’t include links to any servers nor methods to download pirated content, even on the server side. Also it’s nowhere near as widely used as other services so it may just slip under the radar.