The \EFI\BOOT\BOOTX64.EFI is the only file the UEFI standard says it is required automatically lookup from an EFI system partition. There can many EFI partitions but the UEFI is only required to find a single file per such a partition.
efibootmgr -u can show all bios auto created boot entries (don’t touch those, the bios can/will reset them at whim) and the manually created entries that don’t launch a BOOTX64.EFI named file.
The
\EFI\BOOT\BOOTX64.EFIis the only file the UEFI standard says it is required automatically lookup from an EFI system partition. There can many EFI partitions but the UEFI is only required to find a single file per such a partition.efibootmgr -ucan show all bios auto created boot entries (don’t touch those, the bios can/will reset them at whim) and the manually created entries that don’t launch a BOOTX64.EFI named file.