You can manage what posts you see on Lemmy by subscribing to and blocking communities. If you want to get more extensive, even on your own subscriber feed, try applying Regex filters to the RSS feed Lemmy makes from it. (This is also a nice alternative to blocking people while keeping them out of the main feed, for instance if you have them in another one, or hate their posts so much you physically shake)

Great alternative to, say, complaining X instance posts TASS, as if it is fundamentally more unsavory than BBC or Der Spiegel, or asking that Youtube links be banned etc, would be filtering out those URLs with Regex. I love Regex. Teach everyone Regex