Kew Labs UTS-2 has a maximum output of 20W and uses Apple 7.5W and Samsung 9W Fast Charge Protocols
The Kew Labs UTS-2 wireless charger is designed with a powerful maximum output of 20W, ensuring fast and efficient charging for your devices. It supports Apple's 7.5W and Samsung's 9W Fast Charge Protocols and provides a standard 5W charging speed for other Qi-compatible mobile devices such as Nokia, Google Pixel, Oppo, Xiaomi, Sony, and Motorola.
Apple iPhone Charging above 80%
As per Apple's support information - Click Link. Your iPhone or MagSafe Charger might get slightly warmer while your iPhone charges. To extend the lifespan of your battery, if the battery gets too warm, software might limit charging above 80 percent.