I used to have a firehose in Newsblur (between paywalls and sites that died/disappeared altogether or just got too terrible that changed in recent years and now I don't) and its tools were simple and great, and definitely all about user control. It is basically a thumbs up/thumbs down on tags, keywords, author names, and a few other fields. Thumbs up is called "Focused" and shows up as a green indicator in "bubble counts" that there's at least one focused post in a feed. You can switch to a focused-only reading mode as well. (Newsblur also added an "Infrequently Updated Feeds" viewing mode to prioritize the small feeds when you don't have time for the full firehose of your big feeds.) Thumbs down is a dislike and those posts disappear entirely from all the main views (you can still find them in "All Posts" views as red indicated posts.)

It's a real simple algorithm. You control everything about these post organization rules and can update and change them as you wish. I thought it worked rather well back in my firehose reading days.