Did you have it plugged into the recommended charger? I have the Anker Wireless Charger, PowerWave Stand, Qi-Certified connected to the Quick Charge 3.0, Anker 18W 3Amp USB Wall Charger (Quick Charge 2.0 Compatible) and it charges my Pixel 4XL a lot faster than 10% per 10 minutes. I have never timed it, but have placed my phone on it when it shows about 60% remaining and an hour later it is above 90%.
In fact, I have a new one being delivered today since I started to use the wireless charger at night so two was necessary.
However, I cannot speak for a 6Pro at this time.