@MBrandt 

Hi,

Your problem sounds very much like the one another user posted in this thread: https://community.tp-link.com/en/home/forum/topic/593096

Apparently the Realtek chip used in the TX20U Plus and its original driver didn't play well with certain vendor's USB controllers, notably one's based on AMD chipsets.

Anyway, inside the thread posted above there is one reply from Liverpool20 with a link to another post from TP-Link from where you can download a newer driver version. With that particular driver version (5001.15.129.0) I was able to get another brand's AX1800 USB adapter that uses the same Realtek chip to work on my computer's AMD USB 3.1 ports, even in SuperSpeed mode.

By the way, you will know if your TX20U Plus is working in USB SuperSpeed mode if you are able to get data transfer speeds in excess of 40 Megabytes per second. (or use a special system info tool)
 

  @woozle 

Hi Wozzle,

Thanks for your answer and support. Yeah you are right about the PC. 

- AMD Ryzen 7 3700X

- MSI MPG B550 Gaming Plus

- Win11 pro  / 64 - German installation

I tried the solution postet in the other thread and installed. The driver linked there seems o be a rar version of the official driver linked on their driver homepage

https://www.tp-link.com/de/support/download/archer-tx20u-plus/

I tried to install it. As mentioned on the driver download page it only works for the English installation. At least it gives me an error message on the device-manager page, won't start the adapter and continuously  start and shut down the adapter.

I am really surprised it won't work with the B450 / B550 chipset, they are quite common. I think I will cut my losses here and send it back to the vendor, which is really sad. By any chance, do you know an high speed adapter that will work with my chipset?

Kind regards

Matthias

  @MBrandt 

Originally Realtek was the only company who offered a Wi-Fi 6 chip with USB interface. Hence, the device makers who wanted to sell Wi-Fi 6 USB adapters all had to go for that chip.

In the meantime the company MediaTek has also introduced such a chip, but actual devices using that chip aren't readily available in western markets yet.

There are a couple of them sold in China (maybe available via AliExpress?) and the company Net...r has just started marketing their "A8000" Wi-Fi 6E USB adapter.
How good this new MediaTek chip works is still pretty much unknown, though. Getting one of those at this early point would also be a bit risky.

If you have the possibility to install another PCIe card in your computer, then you might want to go for a PCIe Wi-Fi 6E card with the Intel AX210 module. These are really fast and the drivers from Intel are very mature by now.

  @woozle Hey Wozzle,

Thank you for your help and support. I think I will give that PCI-e card a chance, it doesn't seem to be much of an investment.

Have a nice day!