If you are having issues with your sound on your XPS, it is most likely a driver issue.

Make sure that you have the latest Dell drivers by running Dell Command Upadate

Ensure that all updates have been installed.

Still having issues? Check your version of Windows 10

In the lower left corner, type in winver and enter

Check your version of Windows, you want 1904.746 or higher

You might need to force the latest version of Windows 10, see the support article below.

Windows10 Force Update To Latest Version