Well, After some time, I finally got my SlimPort Adapter...
Even got 2 of them. One is direct micro-usb to HDMI Male, which allows to connect directly to a device without the need for an extra HDMI cable !
I happily report that I infirm my previous post ! My problems obviously were related to a malfunctioning adapter.
Both adapters I got allow me to connect to a TV or a VP : image is stable and no flickering whatsoever.
Might keep the LG G3 after all