Can't adjust Picopix volume when using USB-C video?

I connected my Nintendo to USB-C and it works fine, but I’m unable to adjust the volume of PicoPix’s speakers, it’s blasting on full volume which is obviously very annoying. Tried using the remote, and the touch buttons on the device itself, but absolutely nothing happens at all.

Well had similar issue, though usb-c video doesn’t work for me. I’m trying to connect from my laptop’s Thunderbolt 4 port (which obviously has video out) and it won’t work with usb-c video. Instead, a ppx620 is trying to charge my laptop. What’s more, even using TB4 to HDMI doesn’t work too with a regular HDMI cable. When using TB4 as an output, it only work with usb-c to HDMI Samsung’s DEX HDMI Cable. And it works with HDMI-HDMI too.