This is exactly what the laws around fiduciary duty "really" cover. I say "really" because the term is often invoked to justify/excuse scummy behavior from exec

This is exactly what the laws around fiduciary duty "really" cover. I say "really" because the term is often invoked to justify/excuse scummy behavior from executives, arguing that they're legally obligated to behave that way because of fiduciary duty. In reality it just means you must act in the interests of the company, largely to prevent this exact sort of scenario (or an exec just being butthurt or whatever).