No. Flashing stock firmware via SD card does not unlock the bootloader. It only restores the original software. For root or custom ROMs, you need a separate unlock code from Huawei (no longer available officially).
When these problems occur, the most effective solution is to flash the original firmware. For this specific model, the most reliable and accessible method is the method, also known as the "dload" method. Huawei Y336-u02 Firmware Sd Card