If your microphone isn't picking up sound even though it is unmuted in Zoom/Google Meet/Teams, it's possible the device itself is muted, which unfortunately can't be undone from the normal Windows 10 sound settings menu.
Here's how to unmute the microphone device itself:
- Right click the volume icon at the bottom right of your screen.
(Note, if not present, it may be under hidden icons. Click the ∧ button to show hidden icons). - Click on "Sounds".
- Click on "Recording" tab.
- Right-click on your default recording device and then click "Properties".
- Click on "Levels" tab.
- Make sure that the blue speaker button is unmuted.
(It is unmuted on the right; if it looks like the left, click the blue speaker icon to unmute).
- Click "Ok".