I was using the term flashall to describe the method. This is an example of a flash-all.bat, notice the way that the script attempts to flash both slots, multiple partitions and erases userdata; this is good practice in recovering a non-working phone. Many fastboot ROMs already contain a flash-all script.
My first thought would be that the battery never discharged sufficiently but this “discharge to empty” is not as easy to perform as the (old) more reliable “disconnect the battery”!
Edit yes to “official xiaomi”, but you want Android 13 of course. You may be able to recover the phone using the tool and account you used to unlock the phone – I remember using MiUnlockTool to connect to my account and finding an Unbrick option.