Here is what I had to do.
open up a terminal run dconf-editor
then navigate to org > gnome > desktop > wm > keybindings
find the ['<Super>Above_Tab', '<Alt>Above_Tab']
and set it to ['disabled']
then it should free up that binding for you to use else where.
(ps: I used alt grave to switch back one application like you can in mac works well for me and the setting for that is in dconf-editor under the same place
edit
also for those of you that don't know what a grave is, it is the key right above the tab key and to the left of the number 1 key it looks like this ( ` ) or plush shift ( ~ ) its also known as a back-tick and is used in mark down and python as a comment like such
``` code here ```