You must pass the miui eu rom to an sd card, enter twrp and do all wipes,(cache, Dalvik Cache, system, internal storage, data), don't wipe the sd card and then install the rom.
Make sure you install the correct ROM.
Well if it is unlocked you can enter twrp by fastboot, if it is blocked you will surely have to do an edl point and put the original rom using my flash and already unlock the phone, there are tutorials on the internet.
It bothers me that it does not let me download the OTA update, the last time I manually installed the rom the phone crashed as the update was to android 9.
Me molesta que no me permita descargar la actualización de OTA, la última vez que instalé manualmente la ROM, el teléfono se estrelló ya que la actualización .era para Android 9.