The Boot Repair Tool says your
/dev/sda (= the disk the installed Ubuntu is supposed to boot from) has
Disklabel type: dos and
Boot files: /grub/grub.cfg /grub/i386-pc/core.img, so the installation expected to do a legacy MBR-style boot, and installed a version of GRUB tailored for it.
On the other hand, your setup screen clearly indicates your system is set to boot in the UEFI style.
Your system should have not one, but two options for booting an installer from any given CD-ROM or USB installation media. One should result in a native UEFI-style boot; the other, which you apparently have used, is legacy MBR-style boot.
The trick is, you must boot the OS installer using the same style the installed OS is expected to use.
If you boot the installer in MBR style, it won't be able to access EFI boot variables in the system NVRAM, and so won't be able to complete the installation of an UEFI-style bootloader. It will also assume that a MBR-style partitioning and bootloader is what you need: it will create a MBR-style partition table if re-partitioning disks from scratch, and will not create the EFI system partition (ESP).
If there is nothing you need to keep on the system, you should boot the Ubuntu installer again, but in UEFI style this time. Then you should remove all existing partitions, so that the installer can flip the partitioning style to GPT.