I’m sorry, my English is not very good, and using translation software may cause semantic confusion.
In fact, I would like to remind some users of old devices that after repartitioning and restoring system data, they should pay attention to using some parameters of grub-install.
Some old devices only support booting from the default path such as /EFI/BOOT/bootx64.efi, and when you use grub-install without adding the --removable parameter, it will not update to the default path mentioned above.
Actually, my $ESP partition file is the restored backup data. If I had discovered earlier that grub-install cannot create /EFI/BOOT/bootx64.efi by default.
As for why my partition number has changed, I remember that when I last created the system, the partition tool inserted an unused blank partition before the ‘/’ partition, so its partition number was (hd0,gpt3), and this time I manually created the partition, so the ‘/’ partition number is (hd0,gpt2).