Even though DualSense support has been enabled, most of the features, such as adaptive triggers, the controller bolsters has not been added yet.
The recently released PS5 has a strikingly different controller design compared to the previous PlayStation consoles. The new DualSense controller has a much different feel, size, and defining feature. While some of those defining features have not been supported yet, Valve has stated that it has added support for the new controller to the Steam client beta.
Valve put out an announcement on the Steam Community noting the new controller support. It states that this is just initial input support for the DualSense controller. The more advanced features such as rumble, trackpad, and gyro are not yet supported.
It should be noted that support for the Xbox Series X controller has already been enabled by Valve.
Nowhere in the post does Valve mention what I think to be the most defining feature for the DualSense controller: adaptive triggers. At first, I would think that something like that would be limited to the PS5 console itself. However, the phrase “not yet supported” Valve uses in the post gives me some hope that it will be enabled at some point in time.
I have heard from everyone on the team here that the most “next-gen” feeling they have gotten so far while playing with the PS5 or Xbox Series X was the adaptive triggers on the DualSense controller. Just like describing VR, it has been described as something you just have to experience for yourself. Hopefully Steam will support the new feature at some point so that more people can experience it.