Teams Desktop and Microphone

Your microphone works in Windows and Teams on the web, while the desktop test call produces no playback. That narrows the investigation to the desktop Teams path, but it does not yet distinguish microphone capture from speaker playback or a test-call-specific failure.
First, check the exact microphone and speaker selected in Teams rather than relying on the green completion icons. Then join a short meeting with a colleague: can they hear you, and can you hear them? If that works, report the test-call problem separately. If they cannot hear you, confirm Windows microphone access includes desktop applications, even though browser access works.
Because you have already reinstalled Windows and tried the usual fixes, capture Teams support logs with Ctrl+Alt+Shift+1 immediately after reproducing the failure. Send the logs, Teams version, Windows build, and UTC occurrence time privately through your IT support case. Continue using Teams web meanwhile.