I have your answer: you provide a tool for your translators, you don't unleash a bot that makes changes left and right and creates new pages.

Typically, when a new page is written in English, don't automatically generate a version in all languages. When a translator starts creating the page in their language, provide a button to pre-fill with ML translation if they want to.

And for users, you can display the English version with a message, "this is not translated in your language yet but you can read an ML version if you want".

This sounds about right, and should be incorporated everywhere.