Sorry, was out like a broken lamp for a while.
If this is an internal mic, like the built in laptop mic, its entirely possible its simply shit. Laptop mics never last long anyway.
I had a similar issue with my mic that you are describing, you only get one slider with pavu or the default KDE dock for volumes as well, and they arent the best. You cant control line input and output db directly, its just a fader and im not sure which its tied to.
I had to use jack to expose all of them. I couldnt load the attachment you posted with your mic test, but i can guess its clipping which means input gain is too high on one side or the other.
That method i mentioned yesterday is the same method i use to adjust input gain on my own audio hardware.
Sometimes it helps to visualize the problem instead of just listening to it. The LSP plugins pack i had you install yesterday also should come with a few spectrum analyzers. Open the 2 channel spectrum analyzer and route your mic in the way you did to discord yesterday.
Speak into it naturally and look for frequencies peaking above -3db, you also have outputs for the spec ana in jack as well so you can route the output from the analyzer to discord to test on the fly there with the spectrum analyzer running “in line” so speak.
Theres also a pre-amp knob on the analyzer which works similarly to the line gain knobs from the stereo gate. You’ll probably need to turn it down a little if i had to guess.
Let me know how its going over there.