Device is locked

I did a factory reset on my redmi note 4 -gobal edition with mido -ver 8 os.
After reboot a screen appeared wanting password and connection.
I cant remember password and cannot connect to web.

Is there a android os that can be flashed from my pc to phone with a locked boot loader.
Not worried about cloud account,security and warranty issues.
I need a phone that is simple to operate.

I need your advice to solve this problem.

TIA