Ctrl+Shift+U shortcut for writing Unicode characters seems to work inside of the software manager's search bar. Everywhere else such as Gedit, Terminal and Google Chrome pressing
Ctrl+Shift+U does not trigger any special behavior. The interesting thing is that if I create a new user account,
Ctrl+Shift+U works perfectly inside it; While logged into it I am able to use the shortcut properly inside of places like Gedit, Terminal, and Google Chrome.
I tried the solution suggested by Louis in this post, but it was not helpful.
EDIT I answered my own question, see below.