The group used “sophisticated computer scripts” and software to scour piracy services (including the Pirate Bay and Torrentz) for illegal copies of TV episodes, which they then downloaded and hosted on Jetflicks’ servers, according to federal prosecutors.
They probably used Sonarr and Radarr and called it a day (or similar off-the-shelf tools available on GitHub). It's not very sophisticated at all. That combined with Jellyfin and a VPN (or Usenet or a country that doesn't care about piracy) and you have your own up and running. You could also just use free sites with an ad blocker instead of paying $10/mo like the service this article is about charged.