This quote from you shows you don't understand what I have been trying to say.
You're playing on a bootleg cart, not a legitimately retail cartridge. You cannot restore save using GBA Backup tool.
Hence for you and your situation, I said:
Now, in the tutorial:
Step 15: Inject the modified save into the rom file.
Step 20: Flashing ROM to cart using GBABF.
Is the confusion due to a translation error? Do you think GBABF is the same as GBA backup tool? (For the record, it isn't the same).
Your video doesn't help; it doesn't show you using GBABF. It shows you use GBA backup tool (which is incorrect).
All your post and video did is give me the impression that you did not follow the tutorial fully.
Read the tutorial. Follow it step-by-step, fully.
The tutorial isn't just for extracting the save. It is also for injecting the save.
Follow it fully. Only then, can anyone try to help you.