Volume keys on Bluetooth speaker do not work

On my bluetooth speaker, the volume +/- buttons do not work, but other buttons (pause button for example) work fine, and on my bt headset, all buttons work fine

I’ve tried setting up a shortcut (change the volume via a command when the corresponding keys are pressed), but the press of those keys isn’t even detected

How can i make my volume keys work ?

Also (i don’t know if it is of importance), but in the Plasma Bluetooth panel, my bt speaker is categorized as “audio”, while my bt headset is categorized as “périphérique audio” (audio peripheral), maybe this has something to do with the issue ?