My org has purchased a few dozen Latitude 7420s and has noticed that recent variants (ordered within past ~6 months) have an issue where the input level of the built-in RealTek microphone array is very low.  When on collab apps such as MS Teams, WebEx, Zoom, etc. and using the built-in mic, other participants in the call have a very hard time hearing our users because their input level is so low.

If we use an external audio device like a USB headset, everything is fine.

Through trial and error, we've also noticed that if we manually uninstall the RealTek audio drivers through Device Manager, and then click the button to scan for hardware changes, the system will reinstall the driver and the problem will go away.  We thought this was a permanent fix but recently we've seen the same issue recur after we've done the uninstall/reinstall step.  Another uninstall/reinstall fixes the problem again, but it seems now that we're stuck in an infinite loop.  Reinstalling the driver will solve the problem for a while, but eventually the issue comes back and we have to do it again.

We've checked the driver details in Device Manager and as far as we can tell, when we do the uninstall/reinstall, the system is installing the same version of the same driver, so the driver is never actually changing, just being uninstalled and reinstalled.

Running Windows 10 21H2, all latest Windows Updates installed, latest BIOS / firmware from Dell support page, with all of the latest driver updates through Dell SupportAssist.

We've seen this same behavior on at least 20 systems, probably more.

Any thoughts as to the cause and what we might do for a permanent fix?