The Teams desktop app includes an auto-adjustment feature for your microphone that’s turned on by default. But if you're experiencing issues, such as your voice sounding too loud or quiet through your mic, check to be sure auto-adjustment is actually on for you — or turn it off to see if things improve without it.
At the top right of the Teams app, click the three-dot (Settings and more) icon and click Settings from the menu that opens. In the left column, click Devices. To the right of Automatically adjust mic sensitivity, turn the switch on or off.