Highlights are hard to name because different people like different features!
The packaging/dependency situation is pretty much solved now. Cabal v2 has been a godsend. That used to be the big issue. Stack is still around and works fine. ghcup makes installing everything easy. And Nix support is excellent and offers diversity of choice between nixpkgs and haskell.nix (which opens your way to proper x-compilation!)
I don't use it, but the Haskell Language Server is also vastly improved.
The library ecosystem is also the best it's ever been. Again, depends on what you wanna do. But there are more people and companies out there contributing to Haskell OSS than ever.
The compiler and RTS also keep solving problems and pushing the bleeding edge. Compact regions, a new latency-optimized GC, and the eventlog have greatly improved the RTS. And linear types landed recently - still nascent but still a big deal. And dependent types are definitely on their way.
