I don't think that's a good idea. Pretty much all interaction with Emacs is mediated through keybinds. There is no distinction between shortcuts and fundamental behavior. Even ordinary typing is done by having each character on your keyboard bound to self-insert-command. Perhaps there is some way to nuke the global keymap, but then you're left with literally nothing. Besides, this would not prevent various modes from adding their own keys anyway.

You should consider whether Emacs keybinds are actually in the way enough to be bothersome. You can also keymap-global-unset (or keymap-unset) individual bindings that you find problematic. I'd also consider delving into the Spacemacs code to see how they implement their "vi only mode."