Maybe there is something wrong with the software you use to detect the correct polling rate.
Here is the link to all our keyboards' source codes: qmk_firmware/keyboards/keychron at playground · Keychron/qmk_firmware,
in the qmk_firmware/config.h at playground · Keychron/qmk_firmware file, you can see clearly that we have set our keyboard to 1ms, which means the polling rate is at 1000Hz.