Hi Andrea,
Thanks for reaching out to the Microsoft Community. I understand how frustrating it is to deal with a delay when using the mute button.
Just to clarify, does this happen across all apps, or only in specific ones? Also, are you using Bluetooth or USB audio devices?
To start, try restarting the Windows Audio services by typing “services” in the search bar, then restarting Windows Audio, Windows Audio Endpoint Builder, and RPC. You can also try switching to the High Definition audio device driver via Device Manager, which sometimes helps with latency.
Disabling audio enhancements might also help. Press Windows + R, type mmsys.cpl, and disable all enhancements under your playback device settings.
If the issue persists, try running the Surface Diagnostic Toolkit to check for hardware or driver problems. And if nothing works, you might consider a system restore or reset—there’s an option that keeps your personal files intact. Here's the guide: Restore or reset Surface, https://support.microsoft.com/en-us/surface/restore-or-reset-surface-for-windows-e1fd649a-6396-a7de-2e87-7ba3b45e0fb1
Troubleshooting Surface Audio and sound issue: https://support.microsoft.com/en-us/surface/troubleshoot-surface-sound-and-audio-accessories-41bdae2f-677a-166b-1cda-03e44520992e#bkmk_solution2w11
Lastly, make sure nothing is blocking your device’s speaker or mic openings.
Let me know how it goes!
Regards
Edward