Music Assistant’s Android app lets a phone’s physical volume buttons control the selected remote speaker. The optional setting applies while the app has focus, with an overlay showing the speaker’s volume. Andrii Mitnovych’s addition uses the same step commands as the on-screen controls; Android’s media-session behavior outside the app stays unchanged.
Music Assistant
An Android phone’s volume buttons can control a remote speaker
An optional setting sends button presses to the selected Music Assistant player while the app is in focus.