Some time ago I gave up using sonarr & radarr to watch (popular) tv shows and movies because the search just stopped giving decent results. Now I heard that rarbg has also quit.
Have a look at Jackett, it re-produces the search results for hundreds of torrent sites as Torznab feeds, what that means is that these can then be added to indexes for Sonarr and Radarr.
I had issues getting Prowlarr to connect to many sites at all. Jackett just works and has a huge list of working sites, however syncing them all up in the other arr services is a pain which is where https://github.com/AllergicDuck/jackett-sync-ts comes in.