In case you’re wondering, Word supports stylistic sets and contextual alternates. Excel and PowerPoint do not support OT Features. Yet.
But I still do not recommend the Unicode hack because it breaks searching and replacing, copying and pasting, changing fonts, it only works with one particular font, and will likely break other application functions.
Edit: if you want to go ahead with the PUA hack: There is a script in my repo that lets you assign (PUA) unicode values, I think it’s in the Glyph Names submenu.