: Go to Settings > About phone and tap on MIUI Version (or HyperOS Version) 7 times until it says "You are now a developer!". Link Your Mi Account :

Unlocking the bootloader on your Xiaomi Poco X3 Pro may void its warranty and may potentially brick your device if not done correctly. Proceed with caution and at your own risk.

This is where 90% of new users fail. You must bind your Mi Account to the specific Poco X3 Pro.

If the previous owner didn't unbind their Mi Account, you might need to wait 30 days or contact Xiaomi support. Perform a full factory reset and start from Step 1.

If you followed this guide exactly, congratulations—your bootloader is now unlocked. The real adventure has just begun.