Same full sidepanel size than the notification bar or this one, but with these:
Align all elements towards bottom, so free space is above
show input and output volume sliders default with arrow next to them to reveal routing devices and ports
put any application currently streaming audio below the two main outputs with the same dropdown, so one can easily route them individually to certain ports/devices
Same full sidepanel size than the notification bar or this one, but with these: