Why is the charging speed of the POCO F7 Ultra slow?

If the phone is charging while the screen is off:
Our device is a high-performance mobile phone of the new generation flagship platform. The charging power can reach 120W. There are balanced and Top speed for charging with the screen off. If you turn on the Top speed, the phone can be fully charged in about 34 minutes at the fastest;
(1). If the Top speed is not turned on:
Please turn on the Top speed. If you urgently need to charge the phone, you can keep the phone at a suitable ambient temperature (about 25℃) and turn on the Top speed with the screen off for charging. We are sorry to cause you trouble. We are paying attention to the problems you reported and working on improvements. We believe that we will definitely bring you a better experience in the future. Thank you for your understanding and support!
(2). If the Top speed is turned on:
In order to bring you a more balanced and safer experience, the Top speed will also adjust the charging power of the phone to balance the heating of the phone. If you are in urgent need of charging your phone, you can keep the phone at a suitable ambient temperature (about 25℃) and turn off the screen to turn on the Top speed for charging. We are sorry for the trouble you have caused. We are paying attention to the problems you have reported and working on improvements. We believe that we will definitely bring you a better experience in the future. Thank you for your understanding and support!
2. If the phone is charging while the screen is on:
Our device is a high-performance mobile phone of the new generation flagship platform. The charging power can reach 120W. However, during the normal use of the phone, there will be scenarios when the ambient temperature is too high and the phone load is large. In order to bring you a more balanced experience, we will adjust the charging power to balance the heating of the phone. If you are in urgent need of charging your phone, you can keep the phone at a suitable ambient temperature (about 25℃) and turn off the screen to turn on the Top speed for charging. We are sorry for the trouble you have caused. We are paying attention to the problems you have reported and working on improvements. We believe that we will definitely bring you a better experience in the future. Thank you for your understanding and support!