Discord has decided that audio that sounds fine when recorded locally should sound like a cheap speakerphone when transmitted through their service.
I have tripple-checked to make sure it's the correct mic.
I have turned on and off the various settings Discord has for audio.
I have had friends tell me that whatever I did made an improvement or made it worse while I wasn't touching anything.
I am perturbed.
Anyway Discord's bug report lets you upload files so I can have them hear the difference in audio quality while also looking at the logs that Discord will let you record.
So there's that.
This instance set up just for one person, but you don't have to make one for yourself. Visit https://joinmastodon.org/ to find the instance that's right for you.
Are you an academic? Try https://scholar.social/.