I'm trying to monitor the volume of a running project on the master bus inside the "Audio" tab, but the vu meter shows up as inactive.

Image taken from the docs to show that my Master bus looks like the one on the right here, as if it was inactive/disabled, even though I have music and sfx playing properly in the game (AudioStreamPlayers have their bus set to Master). I can't change the volume while running however, but if I set it before running it works.
I would like to see peak volume levels displayed on the VU meter while testing. I can get values with AudioServer.get_bus_peak_volume_left_db() but I assume the VU meter should show these somehow, what am I missing?
On the discord someone said "Live values can be seen using Remote Debug", which I'm not sure I understand. I can switch to "Remote" on the Scene tab but it won't change the Audio section. I can also enable "Deploy with Remote Debug" inside the Debug menu, but that doesn't fix the VU meter, nor am I working with browser/android.
As a reference I'm running engine version 3.3.3.stable.arch_linux using PulseAudio.