It really was this simple:

How to install D-Link DWA-182 Wireless AC1200 Dual Band USB Adapter on Linux Ubuntu

Download zip from here:

rtl8812AU_8821AU_linux on GitHub

Unzip folder e.g. as “/home/mythbuntu/rtl8812AU_8821AU_linux-master”

cd "/home/mythbuntu/rtl8812AU_8821AU_linux-master"
make clean
make
sudo make uninstall
sudo make install

Restart and enable wireless and enter password when prompted (after selecting your own ssid).