Hello @Oreagle
1. Please verify 5Ghz Wi-Fi password by forgetting router 5Ghz Wi-Fi network on mobile device first :
Go to Settings-> WiFi on your phone, Tap (or Long press the router's WiFi name ->Forget / Delete the network
Please reconnect to your router 5Ghz Wi-Fi and it will ask for a password, will it accept your router password?
2. Remove Wi-Fi Profile and reconnect to Wi-Fi signal by manually putting in Wi-Fi password again:
How to connect to wireless networks and remove its profile on windows 10?
3. Use the latest official driver for Archer T1U :
https://www.tp-link.com/support/download/archer-t1u/v2/
If still the same issue, may I know the model of router, can you help collect the mother information of computer and share a photo? Thank you.