While installing Ubuntu 20 (upgraded from 18) the wizard let me choose the key combination for changing input language. The key combination I had in Ubuntu 18 was Super+space, but I didn't find it there and chose "Super" (alone).
I don't know how to change it - in "Settings" it says that the current combination is "Super+space" (which is not the only one).
Now I cannot do anything with any combination with "Super" - it only changes the input language.
See image: I can change the other two, but not the "Left Win"