It is a very common and stupid bug by XIOMI MI/Redmi phones.
It can solved easily but u need to have more patience ?
Even if you connect the charger, you will not be able to see any sign of charging and continues blink (kind of boot loop).
This problem not only faced by you for at least more than a million people.
• Connect the phone with a charger, you may or may not see any sign of charging
• Wait for at least 15 minutes and max of 60 minutes until you notice some sign of charging
• Never disconnect the charger even for a single second while doing it
• After a good amount time you get any of the below,
• Phone booted without any issue :-)
• If not use Power + Vol Up button to boot into recovery mode wipe all,
• I not Vol + Down to fast boot. Keep charging until u see any sign of charging.
• Try with another charger if it did not work
'''Let me know whatever result u get, I will give u the good solution, but do not forget to reply.'''
Cheers,
NallasivanG
https://twitter.com/NallasivanG