Get LineageOS for the Xiaomi POCO X3 Pro
Special boot modes
Recovery: With the device powered off, hold Volume Up + Power. When Xiaomi/POCO/Redmi splash appears, release Power and keep pressed Volume Up until recovery appears.
Bootloader/Fastboot/Download: With the device powered off, hold Volume Down + Power. Keep holding both buttons until the word “FASTBOOT” appears on the screen, then release.