@Plasma 

Thank you for reaching out to the community. 

On the box of the PCI E adapter, can you find the model & hardware version of the device. How to find the model number of your TP-Link device

• If it is model Archer T4E, please  download and install the latest driver 

https://www.tp-link.com/us/support/download/archer-t4e/

• Disable other wireless adapters on PC/ Laptop when use tp-link adapter 
• To help isolate the issue, check if other network device can stream video without buffer, please test at the same location of the PC which installed the adapter.
• Try a different Wi-Fi channel on the router: 

Scan nearby wireless channels using  inSSIDer/WiFi Analyzer app and select a less-crowded Wi-Fi channel and change wifi channel on the router.

if still the same, can I know the model of router, and the network topology?
Please help check the driver version of adapter and computer motherboard info and send us the photos: https://www.tp-link.com/support/faq/2722/

Btw, for the multiple Wi-Fi SSIDs, it can be the SSIDs of the different nodes in mesh or from multiple APs which uses the same Wi-Fi name you could double-check with the router support and see those come from your router/ Wi-Fi system. 

If you use a Mesh system, please check also check if you can disable mesh for the certain network device.