@Biggie 

Hi, may I know the operating system of your computer? Please download the latest driver from the global website for the T9UH V2 first and we will ask the local web admin to update the local website ASAP:

https://www.tp-link.com/en/support/download/archer-t9uh/#Driver

@Biggie 

Hello, thanks for the info. The driver you are using seems quite new.

May I know how far between this computer and your wireless router? With this computer connected to the 5G wireless network, please verify the wireless negotiation speed and send us a picture: 

How to check the associated/link speed on a wireless client

Try to change another USB 3.0 port on your computer. If possible, you can change to another computer to do a comparison test.

Below is an instruction you can refer to narrow down the issue:

How to improve the speed of TP-Link wireless adapters?

Good day.