Thank you,
I've never experienced a keyboard with a high pitched noise, maybe my ears aren't as good as yours or my pc is too loud.
Does your ROG Strix Scope work fine other than the high pitched noise?
What firmware version are you using?
I was searching around to see if I could find anything and came across these steps to resolve it, no guarantees but worth an attempt.
Right click on the taskbar then select Taskbar settings
Click Home then select Update and Security
Select Troubleshoot on the left side
Click Keyboard then Run the Troubleshooter
Right click on the taskbar then select Taskbar settings
Click Home then select Ease of access
On the left side, Click Keyboard
Turn off Filter keys, you may also try to turn off other options there
Right Click the Start icon on the lower left of your screen
Choose Device Manager
Expand Keyboards then Right click the keyboard device
Select Uninstall this device then Restart your PC