One of the fundamental strengths of a federated approach is that I can, with no muss or fuss, see only my local instance.
I understand where you’re coming from, but you’re presuming that most instances are simply clones of each other, and that’s not true. (or at least that’s not how it’s designed to be).
For example, my home instance is mstdn.ca. Ostensibly, with a single button, I can focus my entire Lemmy experience on things important to me as a Canadian without wasting through everyone else’s bullshit. Canadian news. Canadian politics. Canadian hobbies, etc…
You’re idea presumes that all instances are trying to carry the exact same content, which is false.