bind backslash to Tab, then Super + backslash back to backslash

Question

TLDR: I bound my backslash button to tab using xkbcomp and setxkb. Is there a way for me to access the original functionality of the button using Super?

I'm using Linux Mint with Cinnamon, and I have bound my physical backslash key to function as a second Tab button, using a line replace key <BKSL> { [ Tab, ISO_Right_Tab ] }; among others in my keymap file, then loading it using xkbcomp. This works fine. I also mapped my physical Insert key to backslash.

However I was wondering if I could also bind Super + BKSL, where BKSL is my physical backslash key, to insert a backslash \, and Shift + Super + BKSL insert a bar |. In other words, without super, my physical BKSL would function like a tab button, and with super, it would function as the original backslash button.

In xkbcomp, there are things called "groups", where I can set it so that pressing super would shift from group 1 to group 2, and that could meet my requirement, but then that would prevent other ordinary Super + ... shortcuts, since now Super would no longer be Super, but rather the "shift to group 2" button.

Another possibility is the cinnamon keyboard settings, which can bind arbitrary key combinations to arbitrary terminal commands. However, I'm not sure if there's a terminal command to insert a \ or | character at the current cursor. (if there were, then my problem would be solved).