For me the major breaking change on social media is the forcing of non linear timelines. They're required to increase engagement and promoting content but thats the crux of the issue.

I liked the way early twitter worked, I have my bubble being the people I follow and I can see glimpses of the outside from the trending topics and what comes in as retweets, news, etc. Being able to see a thread without being logged in. Seeing analysis of people from the firehose showing different ways to see conversations and the bubbles.

I miss the fact that old tweets died, things had to be relevant to humans to be rekindled, meaning someone had to retweet to keep it alive instead of an algorithm deciding whats important for me based on how outrageous it is.

Bubbles are unavoidable, bubbles decided by algorithms are the worse of all alternatives.