Do not waste time or money trying to unlock the bootloader on the HUAWEI Y7 Pro 2019. The era of unlocked Huawei bootloaders ended in 2018. Use the phone as-is, or replace it with a more developer-friendly model.
Important upfront: If you are looking for a simple, official method to unlock the bootloader of the HUAWEI Y7 Pro 2019, you will not find one. Since mid-2018, Huawei completely shut down its official bootloader unlocking service. This means there is no legal, free, or manufacturer-supported way to unlock the bootloader on this device. How to Unlock Bootloader in HUAWEI Y7 Pro 2019 ...