Honor stopped providing bootloader unlock codes in 2018, making the installation of unofficial "Custom ROMs" or cross-flashing different regional firmwares extremely difficult for average users. Update Your Phone System Online | HUAWEI Support Global
There are critical functional differences between the global firmware and the Chinese domestic ROMs (e.g., BND-AL00 or BND-TL10): honor 7x global firmware
Flashing firmware wipes your data. Back up everything using (official Huawei tool) or manually copy files. Honor stopped providing bootloader unlock codes in 2018,