I think there's a marked difference between seeing boosts of the people you directly follow versus an opaque algorithm that shows you content from the broader network. The former puts you in control: you choose who to follow based on if you like their content and their boosts. The latter is usually tuned towards showing you content that will keep you on the site (and looking at ads), but isn't necessarily content you want to see. As commercial social networking sites become increasingly profit driven, they'll crank the algorithm towards engagement at the cost of everything else. In contrast, a chronological feed of content created by or boosted by the people you directly follow is not "the algorithm".

On Mastodon, I discovered someone via a boost who had wrote a great blog post. I followed them but found my feed was now full of bird photography (their main hobby, and something I don't care for). I added a filter for "#BirdsOfMastodon" (or something), but there were still too many without that tag. So I unfollowed them and now I don't see any bird photos.

Also I recently learned that different people see different comments on the same Instagram post and they to me is something I’d never thought of about echo chambers. Like you could send someone an Instagram post and assuming Instagram has their history they might see different comments than you