First, they're there, and it's absolutely wonderful! I use far more semantically accurate Unicode rather than lossy ASCII approximations than I did back in my old Windows days. (If you don't know the special characters you can get, turn on Keyboard Viewer and whack your keyboard, especially modifier keys, a bit.)
But … I can't customise them. Even back in the days when macOS was OS X and believed in user customisation, these specific shortcuts were frozen and un-customizable. (Like the folder shortcuts in Finder. Maybe it makes sense to you for CMD-SHIFT-D to open the Downloads folder, not the Desktop. Too bad!)
(Boy, I hope I'm wrong and someone will come along and explain my stupidity to me.)