I was going to post this in the “bug” section, but as I began to explore the issue I realized that the feature is working correctly. The correct behavior of this feature is simply undesirable.
Setting the default volume to “disabled” in Rune Audio actually disables the volume control leaving it at a fixed output level of 100%.
Setting the default volume to “disabled” in Volumio just leaves the volume wherever it was at before the last restart rather than setting it to a specified percentage, but does not actually disable the volume control.
Now that I have realized that this setting is not broken in Volumio, just means something different, is there a way to actually disable the volume control all together?
I strongly prefer a fixed output level of 100%, like pretty much every other source on the planet, leaving my preamp to control the volume.
If there is currently no way to do this, why not? This should be a basic feature that most people should want.