For whatever it's worth, Microsoft Word 365 for macOS has only this last few weeks commandeered some of the Option + Shift + <key> sequences.
In order to make things easier for their users, they've assigned our friend Opt + Shift + hyphen (an Em Dash on many Mac input methods) to what they call a "nonbreaking Hyphen." Their support group has said that we can type an Em Dash using Command + Shift + Numpad-hypen. I've replied that most Macs don't come with extended keyboards and numpad keys by default.
They've also explained that if we don't like their key assignments, we can reassign them with their Keyboard Customize… facility. And I've answered that, no, we can't. Their Keyboard Customize… dialog doesn't acknowledge "Option +" or "Option + Shift +" sequences, because overriding the mac's Option+ sequences would be a bad idea —because that would clobber the input methods.
I've logged support items with them explaining how this is a serious problem for them to overstep and begin commandeering keys from the macOS Input Methods, especially since some of the symbols we're using there support accessibility methods.
So while we try to talk them into that, I've installed Karabiner Elements and I've written an override specifically to replace "Option + Shift + hyphen" events with "Command + Shift + Numpad-hyphen" only when Microsoft Word is the bundle identifier of the frontmost app.
It works, but it's annoying that it has to. Not that it's a big difference. I have both Mac and Windows versions of word on the Mac here. (Thanks, Parallels.) I have to use Karabiner to get the Windows keyboard going into WinWord without interference from macOS. Fortunately, Karabiner will distinguish between the two keyboards and any keypads I attach. Makes advanced typesetting much easier.
Ross