The only user that can edit post is myself aka the admin. I have some weird setup where users can indeed inject not code but text to the backend(and incase i have missed something which is very possible then i could accidentally perform do_shortcode on the page which contains user code). Which means that they can potentially trigger shortcodes.
So i simplified the strategy by avoiding all sorts of functional/powerful shortcodes and instead only use shortcodes for displaying simple html etc…
So from my understanding of your writing, as long as i make sure that user roles dont have access to edit posts, we should be safe?