The fail dangerous doesn’t work if you block it in the torrent client, so you’d have to actually download it but then sonarr would mark it as failed and not get stopped from downloading new items for that show. Neither option is perfect.

See if you’re getting these bad torrent moreso from one particular tracker and then rethink about using that tracker.

Best option is trying to get into some private trackers, pretty easy looking for open signups on lemmy or the dreaded reddit.