I purchased a TP-Link Archer TX50E AX3000 a few weeks ago. 

For ~2 weeks it worked fine, and then it suddenly would not connect to the internet anymore. Internet on all other devices worked fine, but on the Wifi adapter would continually say I did not have a valid IP configuration. Nothing worked until I swapped the card into a different PCIe slot, at which point it started to work again. 

Now, after a few days, it appears to be back to being broken. This time it will still connect to the internet, but my 1GBPS connection will randomly drop to 0.5MBPS. Running the troubleshooter will return DNS related errors. After a while it will seemingly return to normal. A list of what i've done so far:

• Reset the modem/computer
• Checked for windows updates
• Disabled firewalls
• Uninstalled drivers and re-installed most recent
• Ipconfig release/renew/flushdns
• Reset TCP/IP stack
• Manually set IPs/DNS etc
• Swap PCIe slots

Any suggestions? Feels like this thing is completely broken.