I'm not sure if this is Musk-related, but Twitter has definitely changed.
* More ads, not as easy to hide them with traditional blocker
* More bots - I'm a baseball fan and follow a lot of baseball people, and players in particular are big on custom tshirts that are only usually sold by a special MLB-licensed vendor. However, there will be tweets with a photo or video and multiple replies by scam bots saying "tshirt available at xyz.example!!" and then a plethora more bots replying to that thread saying "thanks just ordered mine!" or variations of that
* Not sure if "bot", but there are a few OnlyFans style bots or even maybe just users where I constantly see them reply tweets but only one at a time; I block them every time because I'm not interested, only for another variation with slightly different name but the same "person" showing up the next day or so.
I don't know what's changed for those things to happen, but they've definitely increased or outright started just in the past year.