I recommend doing this as a net/minimum install with Manjaro (no desktop manager attached with the install).
pacman -Syu
reboot -h now
pacman -S xorg xorg-server deepin deepin-extra
nano /etc/lightdm/lightdm.conf
greeter-session=lightdm-deepin-greeter
systemctl enable lightdm.service
reboot -h now
Thanks, man! saved me!