Go into your torrent client like qbittorrent settings and you can enter unwanted extensions, *.scr, *.exe, etc. Same if you use a usenet downloader like sabnzbd or nzbget. Then if sonarr or radarr attempt to download an unwanted extension your torrent downloader will not download it.

How is it even downloading that? Wouldn't the sonarr quality profiles grab an actual video file? An exe has no resolution for instance.

Also in my case most video files are transpiled automatically so jellyfin has to work less when serving, so the transpiled would fail. Shit would never run unguarded.

Not necessarily block, but it will clean them up and blacklist them. Look up Cleanuparr