Over a million people joined Bluesky after the election and seem to be using it. Also a lot of news & media companies have moved over too. So I would assume that at least that many users have disappeared from X or their activity has diminished. On top of that all the bots have gone home now the election is over so the amount of activity must have suffered. And Bluesky is basically old Twitter so people are settling into it and liking it.
I would advise anyone who still using X to give it a try. And if they want to use X for whatever reason - uninstall the app, install Control Panel for Twitter into their mobile browser and browse that for a relatively bullshit free experience - no ads, no algorithmic lists, just what you subscribe to.
