I managed to solve it, even though the bootloader was blocked.
If you already have the bootloader unlocked, skip to the part of the mi flash tool, if it is locked, follow the step by step.
We will need:
https://c.mi.com/in/miuidownload/detail?guide=2 which is the flashable rom by fastboot
We will also need the miflash
And for those who have a locked bootloader, there is a way to unlock it using a tool called mtkclient, available at this link
https://github.com/notmyst33d/mtkclient-gui/releases
you will first need to unlock the bootloader, for that you will use mtkclient, when downloading you extract the folder and double click on the "start" file, YOUR DEVICE MUST BE DISCONNECTED FROM THE COMPUTER, when opening select option 3 - bypass SLA/DAA, it will keep showing a repeated message until you connect the cell phone in BROM mode. To enter BROM mode, with the mobile phone on or off, press volume +, volume - and power at the same time (for this part it is interesting that before pressing the buttons you are seeing something on the screen, so you will notice that the screen turned off when pressing the buttons), when you have the buttons pressed and the screen is off, you connect the cable and release the buttons, immediately the script will start.
When you finish this part do the same thing in the same file, but now it will be in option 1 - unlock bootloader.
When finished, your device will try to boot and you will notice that the bootloader is unlocked.
Now just install the indicated rom (or any other less than 12.5.5.0) using mi flash.
Detail, when using mi flash, make sure you don't block the bootloader again.
AND DO NOT UPDATE THE DEVICE UNTIL A FUNCTIONAL ROM IS OUT