Any Linux distro should work for the setup you want. I have radarr, sonarr, sabnzbd, deluge and jellyfin running on an Arch setup, but something more accessible like Ubuntu or Debian should work fine (although I’m not familiar with whether the Pi4 can power those heavier distros). If you’re comfortable with the command line, it doesn’t matter much which distro you pick since you can install and configure all those apps over ssh.