Thank you for pointing that out!
For some of us, with Ubuntu / pulseaudio, there is another file path to check:
/usr/share/pulseaudio/alsa-mixer/paths/analog-input-internal-mic.conf
A bit confusing, as both files are present.
For a temp fix, someone could run “alsamix”, F4 for Capture, LEFT-ARROW to “Internal Mic Boost”, DOWN-ARROW till dB gain is 0, ESC to exit.
If you’re still having Input Gain issues during calls, try editing /etc/pulse/default.pa and replace
load-module module-echo-cancel line with
load-module module-echo-cancel aec_args="analog_gain_control=0 digital_gain_control=0" and restart pulseaudio with pulseaudio -k