You could try https://alsa.opensrc.org/How_to_use_softvol_to_control_the_master_volume (I haven’t tested it, just found it by searching). Otherwise, I think using pulseaudio will give you a software volume.
You could try https://alsa.opensrc.org/How_to_use_softvol_to_control_the_master_volume (I haven’t tested it, just found it by searching). Otherwise, I think using pulseaudio will give you a software volume.