Get your own deduped river
Export an OPML file from your RSS reader (tt-rss, Feedly, Inoreader, Miniflux — they all have one) and upload it here. You get back a private river and a single RSS feed with duplicate coverage collapsed to the best article from your subscriptions.
Up to 150 feeds per upload. No account needed — you get a private link instead. Feeds you add are fetched politely (conditional GET, backoff) and may appear in the public river.