Note:- Now xda forum for MI6X is opened at https://forum.xda-developers.com/mi-a2/xiaomi-6x-wayne in 13th Nov 2018...
So you can find more from there..
Before this thread is in general Q&A forum created in 16th Aug 2018..
Now it has moved to wayne forum for convenience of users
After searching sometime for Rooting, TWRP, Custom ROMs for MI 6X codenamed wayne I didnt find a forum or thread for MI 6X and I found these from google .....
I didn't have this device but a friend asked in a thread of q&a