So I have found the main cause of the very short battery life in standby, and here is a tutorial on how to modify your LUXE.
I also understand that not everybody will feel like the doing the modification to extend the standby time to about 3.5 days with the stock battery (10 days if you also use the opportnity of opening the case to change the battery for a 3500mAh), so all backers still have the choice to send it back and have a refund.
Here is the tutorial :
We will be out of stock for a while, When we will receive the production batch, then we will have to open all devices to do this modification. But the price will have to be increased a bit to cover all this costs.