Thank you all for the suggestions. The solution ended up coming as a combination of various searches I made that had overlapping similarities.
Below are the steps description of what in the end allowed me to resolve the issue.
First I needed to confirm that GRUB was still present. I did that by following this post answer in order to access the content of the EFI partition while in Windows.
As explained in the post, I mounted the EFI partition with the command below:
mountvol P: /S
Note: The letter P was a suggestion that come from the link above but any other, as long as it is not already in use, would also work.
Then navigating inside the partition I was able to confirm that besides the WindowBootManager, ubuntu directory was also available (This meant finding the GRUB file associated with ubuntu inside the EFI partition. - \EFI\ubuntu\grubx64.efi).
After confirming that required boot file listed above existed, the boot order configuration needed to be changed so that GRUB could manage the boot process. For that I followed this other post answer which explained that executing the bcdedit executable enabled a way to assign other EFI entries as the initial boot manager. That was achieved by executing the command below.
bcdedit /set {bootmgr} path \EFI\ubuntu\grubx64.efi
Note that the path is the same we got from the previous step.
The command returned success. After that (until now) when I reboot I am redirected to Grub to select the operating system.
