Hi @thorlokk. It's not that they have been removed, but that they haven't been implemented yet. Arduino IDE 2.x is a complete remake of the Arduino IDE from scratch. It still hasn't reached full feature parity with the classic Arduino IDE (though it does have new features), but Arduino decided it was the right time to open it up for beta testing by the community.
I also very much miss this feature. Every time I load Arduino IDE 1.8.13, I end up with updatable library and boards notifications, when I didn't even realize I was using outdated versions in Arduinno IDE 2.x.
You are welcome to open a feature request in the tracker here:
That will make sure the Arduino developers are aware that it's missed and keep it on the roadmap.