I'm afraid this is one of those features that was just really badly thought-through from the outset, when the new fullscreen paradigm was added, & hasn't been fixed yet.
- You can only use key commands to go directly to numbered Spaces.
- Fullscreen Spaces don't have a number.
- Catch 22
Best you can do is use the number keys to get to the last numbered Space, then Ctrl ⌃ → to get to the fullscreen Space you require.
Yet another reason I never use fullscreen.
BTW, according to your Shortcuts picture, you only have one Space set up. The Ctrl ⌃ [num] shortcuts are added automatically [but not activated by default] as you add each potential Space.
Compared to my 7...
Safari full-screened to the right, as an example. Spaces have numbers, fullscreens have names.