Zuck wasn't hired, he founded the company and structured it such that he would always have a majority of voting rights and control over it. It is very, very difficult to remove him unwillingly. If he wants to bet the entire farm on metaverse and sink the company, ruin shareholder value, layoff everyone, etc. then he can and seemingly will do it.

At some point there will probably be moves from hedge funds and big share holders to sue him for breach of fiduciary responsibility. It will be interesting to see how he responds.