If your laptop came with Windows installed from ASUS, then the OEM partition was there. Doesn't matter if you formatted your OS drive without a backup of any kind.
You could checkout my "Sticky" labeled : "Make a copy of your eSupport Folder before formating your OS drive!" to get a copy of your eSupport Folder and rebuild your OS to near OEM level.
Honestly, I think you had a custom audio configuration as I don't recall the ASUS use of Waves MaxAudio with Realtek HD for several years. This is not to say your laptop didn't have that option, but since you say Windows updated the audio driver, I think you had an outdated program/driver installed. If you Google Waves MaxAudio you will find that some Dell laptops still use the programs/drivers. Could it be someone installed program/drivers from Dell?
Contact ASUS support, get a RMA, and return laptop to them to install new OEM drive.
Last ditch effort to restore your ASUS laptop to factory fresh configuration.
You can order ASUS Authorized Windows Notebook Recovery Media. Here's the link. It's not free but the service will restore your OS drive to OEM specs.
https://www.asus.com/us/support/article/782/Good Luck
G752VSK, G75VW-3D, G51J, G1S
Homebuilt Windows Server