Stuck at MIUI logo while booting.

After my phone died when battery was drained. I charged it and when it booted up, it did not went passed the MIUI logo. I have tried fastboot clear cache, but the phone is locked. I also tried recovery mode boot in system and safe mode, to no avail.

I don't want to lose data on my phone so I did not try to factory reset on recovery mode. I've read flashing stock firmware would help but I can't find official flashing tools and firmware from non-sketchy looking websites.

Any Idea on how can I resolve this issue without losing data on my phone?