Restore backup of WinEFI or UEFI (not sure) that boot-repair made

To undo & to rename files to their original names, you just need to tick the "Restore EFI backups" option of Boot-Repair.

I also suggest a full backup of your efi partition.

It looks like boot repair ran its "buggy" UEFI rename function. I am not sure it is always required, but it is for those UEFI that internally hard code UEFI to only boot the Windows efi file. So Boot-Repair renames the Windows file and makes grub2's shim be the Windows file. The UEFI thinks it is booting Windows but is really booting grub2 and then from grub2 menu you can boot Windows.

Then renamed /EFI/microsoft/boot/shimx64.efi to bootmgfw.efi Actual Windows boot file, originally bootmgfw.efi. /EFI/Microsoft/Boot/bkpbootmgfw.efi

With the renamed file you cannot directly boot Windows from UEFI menu as it really is shim. So that is why both UEFI entries boot grub. If you can directly boot Ubuntu entry you do not need the rename.

You can also manually rename files by changing the bkpbootmgfw.efi back to its bootmgfw.efi name.

And you should have another copy: Windows UEFI install should have backup of bootmgfw.efi here: C:\Windows\Boot\EFI\bootmgfw.efi from a working Windows x86_64 installation.