The "Global Firmware" became the holy grail for these users. By flashing the official Global ROM (PD1612BF)

Wait for the progress bar to complete. Do not disturb the cable connection.

Use resources like HardReset.info or YouTube tutorials that link to official, virus-free stock ROMs.

: Eliminate region-specific Chinese apps that you don't use.

Go to Settings > About Phone and verify your model number. Common variants include the Vivo Y66, Y66i, and Y66L. Ensure your firmware file matches your exact model name.