Is the latest driver for video card/Monitor installed on your computer?
Does Device Manager report problems (yellow triangles with ! mark)?
You can find the latest driver for the Monitor here:
ROG SWIFT PG27UQ Driver & Tools | Monitors | ASUS USA
Is there everything OK in Device Manager, no warnings (yellow triangles with exclamation marks)?
My first thought, based on your statement "they have been working...", is that some updates modified the settings or new buggy driver(s) were installed. You can check when were the latest updates...
It seems that you have tried pretty much everything that could fix the problem.
I suppose the driver is not good (buggy).
That can only be fixed by either removing the bugs or by making a new driver (programming stuff).
The other solution is to buy another headset.
Linux is a very good solution for File Sharing. Did you ask for help with Linux?
You can use either SAMBA OR MySecureShell SFTP server. I have even published a book on MySecureShell server.
RETAIL license can be used on any computer at a time. It doesn't matter if you change the hardware.
It would help if you answered the following questions:
1) What VPN service do you use?
2) What error messages exactly do you get?
3) do you get the same error messages regardless of the web browser you use (supposing you tried more than one)?