I've been a director on non-profit boards for 20+ years. These were small organizations, nothing at all high profile. Well-run boards with honest, dedicated members have little to worry about. Thing is, fundamental to board integrity is the concept that directors must avoid even the appearance of conflicts of interest. If directors adhere to this advice serious harm is unlikely.
The OpenAI board members were vivid examples of massive COI. It was bound to blow up in their faces. They really should have known better. Hard to believe such smart people could act so wrongly. Truly unbelievable.
Likewise, but for two different for profit companies. I figured that if I wanted to do that sort of thing I should focus on it entirely and first bone up on the exact ins and outs and I don't think I have the right temperament for such a role (to put it mildly).