If I understand correctly, you deleted the EFI partition.
But even if you still have the EFI partition, given the numerous attempts you have made on that partition, I think you should delete it and recreate it with the procedure that I post to you later.
Ok, one year ago I helped a friend to restore it and copy the Windows EFI files.
We followed several guides on the Internet, but the only one worked was
this guide.
You must have an Win install disk (or usb).
If you see the Microsoft Reserved Partition (usually 128 MB) you should delete it and then recreate it follow the guide.
This partiton is not strictly needed, but Win10 (and some applications) uses it to perform some recovery actions, so I recommend it.
After that, you will be able to restore the grub too.
Please pay attention to follow the tutorial carefully and don’t delete/touch your manjaro or data partitions.
Make a backup of your Manjaro partition(s).
Good luck! 