Data from alsa-info.sh shows that the onboard audio codec has 2 capture inputs
card 0: PCH [HDA Intel PCH], device 0: ALC887-VD Analog [ALC887-VD Analog]
card 0: PCH [HDA Intel PCH], device 2: ALC887-VD Alt Analog [ALC887-VD Alt Analog]
The audio controls for the card show both inputs are configured to use the Front microphone jack
Simple mixer control 'Input Source',0
Capabilities: cenum
Items: 'Front Mic' 'Rear Mic' 'Line'
Item0: 'Front Mic'
Simple mixer control 'Input Source',1
Capabilities: cenum
Items: 'Front Mic' 'Rear Mic' 'Line'
Item0: 'Front Mic'
Previous users with similar audio codecs have reported problems with audio quality when one microphone jack is connected to the 2 capture inputs
the GUI-equivalent controls in alsamixer for configuring the microphone connections are hidden in the window overflow in the screenshot
(This is one of the reasons why screenshots are unhelpful for troubleshooting)
I suggest you use → key in alsamixer to find the control for Input Source,1
and ↓ ↑ to change the capture input to Rear Mic
and then use this command to save corrected ALSA settings
sudo alsactl store