Maybe it is then time for having something that is beyond "use strict" at the beginning auf a JavaScript document as one option to use the statement.
I think a config object in which you define for script options like sanitization and other script configuration might be helpful.
After all, there almost always need to be backward compatibility be ensured, and this might work. I am no spec guy, it is just an idea. React makes use of "use client/server", so this would be more central and explicit.