Not all laptops with usb3 are capable of transmitting video over the usb3 port, even with a usb3 to HDMI adaptor. You need to check the spec.
You can either get a DisplayLink monitor which uses USB3 to send the video signal or a USB3 docking station with video outputs.
He stated laptop
Not sure if you mean a desktop or laptop. Very rare to find a desktop with only one monitor port. VGA for a second monitor is more than good enough for most things, Unless you are into games or video processing, this monitor is more than good enough. A suitable computer for games is around £1300, and obviously the moinitor will be in a different league.
Depends if you can get a docking station for your laptop? I run 2 external monitors from my HP (G850)laptop but it’s in a docking station