I have just deleted everything using the Partition Manager from a Live Session and reinstalled Solus Plasma on a clean drive. It still does not work. I have no options available at start.
EDIT: Update #3
I have just discovered that Ventoy has an option in it's Local Boot menu to find a "BOOTX64.EFI" file and start whatever that file starts. This is another way to start the system.
Now that I'm in the system, again, I was thinking of running a "sudo update-grub" command but it doesn't work, I get "command not found". I get the same result for "grub-mkconfig". : (