It seems a little odd that you are getting hearing USB disconnect / connect notification sounds in this way, as the ROG STRIX XG27VQ does not feature a USB hub of any kind. I assume also that you are not using a DisplayPort hub of any kind. If it's simply a matter of disabling the sound, you can always go to Control Panel > Sound > Sounds, there you will find a list of program events and the related sounds assigned to each. From there you can try search for the relevant sound you are hearing and then select 'none' disable it.