More goodies coming to the Steam Deck and Steam Desktop Beta, as Valve sure do like to work quickly to solve bugs and add features. Once again a lot is shared between the two but there are some differences.
Steam Deck Desktop / New Big Picture Mode / Overlay Wifi Sprinkler Valve Controller
Just for Linux desktop, Valve also solved this issue:
Desktop changelog / Steam Deck changelog.
What are you current most wanted fixes?
Gas Cylinder Switch Actuator For me, I really want them to figure out what's causing the New Big Picture Mode to perform so poorly on Linux. It's pretty much unusable with NVIDIA.