Keyboard shortcuts are a mess in all common DEs I think. Windows mostly use win+something for commands that have a scope wider than the current application. But there's always ctrl + x, c and v.

Mac might have a better tought out keyboard [1] with @ on a key of its own and \|/ all available on a single key just using modifiers (isn't mentioned anywhere in the manual or help system and not printed in light blue on the keys).

I think the biggest problem everywhere might be that there is no scoping. E.g. if ctrl + something would never affect anything outside of the currently focused window then any application could happily use any and all ctrl-shortcuts for its own purposes. In the same way Super could be defined to only be available for DE-level shortcuts (e.g. cut, copy, paste, switch windows etc).

[1] Also note that apple laptops like ibm/lenovo laptops have fn|ctrl instead of ctrl|fn. Unlike lenovo though it c a n n o t be remapped. (At least it was not possible last time I tried back in 2011.)