1. There is no EFI system partition with FAT on a virtual disk
2. There is no EFI loader file called EFI\BOOT\bootx64.efi
Try to locate it manually selecting "Boot Maintenance Manager" -> "Boot From File"
Also it would be helpful if you provide a screenshot of this window called "File Explorer" if you won't be able to locate EFI loader.
In common case you shall press on entry "EFISECTOR", [PciRoot(0x0)/Pci(0, 0x1F, XXX)/{Ide,Scsi,Sata,NVMe}/HD(X,GPT,XXXX], then "EFI", then "Boot", then "bootx64.efi"
It would be more helpful if you choose "Send Technical Data" and share its ID. At this moment I know nothing about VM you trying to start: how many disks, what guest OS and so on.