Some non-Realtek audio cards are mistakenly detected as Realtek by Windows. I would uninstall the Realtek software from Settings, Apps, Installed Apps and restart. If that doesn't work, search for Device Manager, click on the Realtek audio device and uninstall it, then restart. If you know your motherboard or PC model, go to manufacturer site and download the audio driver from there. Most likely is not Realtek. You can see exactly what hardware you have with a utility such as Aida64 or Speccy. If that doesn't help to identify your audio card, as a last resort you can use a driver tool such as Snappy Driver Installer to detect your hardware and install a driver from their database. To avoid any incompatibilities and other issues, install only the missing drivers or the ones your want to update. Avoid updating all drivers!
