Deleted Comment
FWIW, and I'm not sure if this is against terms here, but I use newsgeek for the former and giganews for the latter. Both are paid services but reasonably priced imo. When I can find something on Usenet, it typically downloads with speeds > 10MBps vs. torrenting which can exceed that but is usually much slower.
You can use whatever client you want. I have the *arr stack mentioned elsewhere in this thread as well and SABnzbd is the recommended option there.
And I don't have to play the 'which service has this?' game.
I don't know if I would use the word approachable
And there is one singular app which supports RCS.
In many ways, it's a regression from SMS. In that SMS is somewhat universal, and RCS is so specialized it's almost worthless.