GNU/Linux Elementary OS Tp-Link Archer T4U v3 Driver Setup – Step-by-step Guide
The linked tutorial shows you step-by-step How to Install Tp-Link Archer T4U v3 Wireless 802.11ac Driver in Elementary OS GNU/Linux desktop – Step by step Tutorial.
And the Elementary OS Linux Tp-Link Archer T4U v3 Setup is based on the Realtek rtl8812BU Chipset Driver Installation.
So the linked guide explain How to Download and Install the rtl8812BU Linux Driver.

GNU/Linux Elementary OS Tp-Link Archer T4U v3 Wireless Driver Installation Guide
On the Driver Download page, take into account that the Morrownr release is currently the recommended choice for this Dongle.