I didn’t say anything about Usenet in the comment you are replying to. The point is Radarr/Sonarr are not Usenet. They are just front ends regardless of which service you are getting content from. Whatever download speed you get on that service is what you get, they have nothing to do with it.
I’ve had plenty of torrents download at high speed, is it less reliable than Usenet? Yes, but It’s also free. I’ll wait a day or two if I have to if it saves me money.