Hi Derek,
I have seen a few similar reports where Upload Audio button is responsive. I can confirm it from my end as well:

Please take a moment to report the problem.
Please go to Help > Feedback button > Report a problem > Write this feedback:
Problem Title: Upload Audio button is unresponsive in Microsoft Word Transcribe feature
Problem Description:
I am experiencing an issue with the Transcribe feature in Microsoft Word.
When I navigate to Home > Dictate > Transcribe and click the Upload audio button, nothing happens. The button appears to be unresponsive, and no file selection window opens.
As a result, I am unable to upload audio files for transcription.
Expected Behaviour: Clicking the Upload audio button should open the file selection dialog, allowing me to browse and select an audio file for transcription.
Actual Behaviour: Clicking the Upload audio button does not trigger any action. No file picker opens, and no error message is displayed.
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I hope this information helps. If you have any more questions, don't hesitate to reach out. Wishing you good luck!