If the Type-C port on the Xiaomi Pad 7 Pro isn't connecting to your projection cable for screen mirroring, first try reversing the Type-C connector to see if that resolves the issue.
If the issue persists, try using a different adapter. The Xiaomi Pad 7 Pro supports mainstream adapters such as Type-C to DP, Type-C to HDMI, and Type-C to Dongle (HDMI, DP). However, some adapters can not meet the tablet’s screen mirroring requirements.