Gossip surrounding Mi 10 Pro’s charging speed have started as long ago as December 2019. Now, 66W has been confirmed by an XDA forum user; that person supposedly dug it out from the MIUI 11 code.
Very little is known about Mi 10 Pro, only that it will run on a Snapdragon 865 CPU. We will learn more on its official release, which may take place on February 11.