Question about Xiaomi Mi Wireless Charging Stand

I was only able to charge the Xiaomi Mi9 and Mi10 really quickly. Charging an iPhone 12 was like charging at a snail's pace. So the 7 watts from the previous poster could be right. I have the feeling that this is a proprietary charging technology from Xiaomi. I would rather buy a 10 watt charging mat or similar if you don't own a Xiaomi Fon.
Provided you have the right plug-in power supply.

Hello even if the device has 20watts, an iphone can only be charged with 7 watts and a samsung 15 watts, so it does not charge the device quickly with that