Well, 143 hours passed ... and unfortunately still no luck .
The MiUnlock app stops the process at 99%.
First the "Device Verified" ticks green. OK.
But at the end an error message shows: "This device is not activated. Activate it and try to unlock again".
My MI Account is linked to the phone and previously had verified it: "Congratulations! You can be assured the phone you have purchased is the official international version.".
My guess is that I do not have a SIM with a data plan, just calls. For linking the device to the account there was a statement: "Make sure your device can connect to the internet using mobile data." So I borrowed another SIM card, but typed my phone number to get the SMS.
Yesterday I tried to do the same, but still ""This device is not activated ...".
In my "Mi Unlock Status" the account and the device show, but there is another field for the SIM that states "Not verified". I change the phone recovery number to match that of the borrowed SIM card with the hope that it will change the state. Nope. I activate "Find my device" (I read it somewhere it was necessary) and let Xiaomi know where I am without wifi and the SIM data on. No luck. I also read somewhere that I also have to sync calls and messages with their cloud but it failed in all my attempts. I am not paranoid, but all this requisites and opening the File Manager app and read a message asking permission to share data or receive personalized ads its giving me the creeps. I need UBports right now .
I know that there is not any official information and all the requisites I see online seem different or, even, contradictory. I think that I will have to borrow the SIM card a bit longer, do some stuff with it and wait until Xiaomi recognizes I use it in this device. How long do you think it could take?