Please tell me how to adjust the speaker volume when joining a Teams meeting as a Direct Guest on a PC with a touch panel.

Hey All

We’re using Zoom Rooms with a combination of Windows PCs, mobile touch panels, and the Neat.Bar BYOD model.
When joining a Teams meeting, the buttons to turn the camera and microphone on and off appear, but the slider for adjusting the speaker volume does not show up.
If anyone knows how to display the volume control, please let us know.

We use a mobile touchscreen instead of a tablet as the controller because it’s more affordable, and due to internal security restrictions: we cannot use Android tablets, and iPads are difficult to manage.
I’m aware that this can be done using the Room Controller on a smartphone or PC, but that’s too complicated for general users, so I’d like to handle everything directly on the touchscreen.