A small contribution from my side (and not to pour gasoline on fire, it is just coming from my own 2-weeks experience). I am also adding two pictures of the phone and the case with the Qi-receiver in-between to show how it looks like after my small modification on the protective case:
I have been using the Nillkin Qi-receiver since 2 weeks. Instead of placing it INSIDE the phone (thus under the backcover), I placed it between the phone and the protective case, after removing the sticker and double-sided tape on the receiver to make it as thin as possible. Subsequently I made small cuts and removed a small piece from the bottom rear side of the USB-c opening of the protective case so that the cable can move freely and the plug can be (almost) easily plugged and unplugged whenever it is necessary (for example when you don;t have any wireless charger around and have to use a cable to charge your phone). The bulge on the back side of the protective case gives me some discomfort of course, but it is not 'unbearable’so to say. It is barely visible from distances >50cm if you don’t look very carefully; and it doesn’t feel spongy or unstable in your hand when you hold the phone. The plug is level with the protective case so it does not hit anywhere when the botom of the phone touches a surface. And the most important finding for me is: The charging temperature during a charging cycle (normal charging, not slow charging) from +/-60% to +/- 85% has been 28 grades celcius max. while it is between 35 and 40 celcius during the cable charging(normal or quick charge, with or without original Fairphone cable) in the same ambient temperature.
I think this could be a viable solution for the majority of the wireless charging supporters who wants to have a FP. It might be also applicable for the FP4 and its soft protective case.
