2D audio with volume falloff

For my usecase, I would like to add an audio source to an avatar, that has 2D audio (stereo separation, left and right channel work as expected) or ambisonic sounds. But if I do that, the volume can’t be controlled by the distance from the audio source. I’ve tried all variations of audio source options, custom curves and spatial audio, but I could not get it to work. It would always play at max volume.

Is this a bug in VRchat or have I just not found the one correct solution for this?