To be honest, Twitter/X has been a sewer for a good decade or so. The only thing that has changed is the kind of sewage that is allowed or encouraged to flow through it.
Elon's checkmark system is the equivalent to the hot weather that caused the Great Stink [0].
Which is natural when you effectively disband the safety teams and allow all previous banned accounts back onto the platform. Also where as Twitter at least tried to comply with codes of practice, X has simply just given up.
Also a lot of it has to do with Musk being the face of the platform and endlessly trying to start culture wars.
The new mayor of Twitter/X has decided that he likes the smell of his own shit and that everyone else should be forced to experience it, so we get piles of vapid idiotic blue check marks dominating discussion rather than the comments that are considered best by the crowd.
Despite all the shit flowing in the streets, it can still be somewhat avoided, and there is valuable information on Twitter that I can not find from any other source. High quality curators of information about computational biology, energy, housing politics, etc. do not have as large a presence on any other social network yet. I just need to avoid any viral tweets or anything from the "For You" or trending topics, and I can avoid stepping in the worst of it.