As you state
You should NOT jump into AUR and NOT while using stable branch (default).
→ [Need-To-Know] About Manjaro and AUR
No driver for Nvidia is active - but the output suggests that your card is supported by the 470.xx driver series
The message you supplied provides a hint to what you need to do
Manjaro is largely a self-service Linux distribution. Response to any topic is provided by community members like yourself - so you cannot request hand holding and extensive guiding - but any community member may choose to and if that happens you should thank the member(s) involved 
→ Manjaro Hardware Detection - Manjaro
Manjaro Settings Manager GUI - provides a GUI to install drivers
→ Manjaro Settings Manager - Manjaro
The CLI utility mhwd can be used as well
Selecting the driver based on a database
sudo mhwd -a pci nonfree 0300
Specify the driver to install
sudo mhwd -i pci video-nvidia-470xx