Woz, maybe he actually was a nerd.
Indeed. Even in the middle ages rich people leaned heavily on charity to whitewash their legacy. I mean, the Catholic church even made this accessible to the masses through indulgence.
He was also the poster boy for tech nerd assholes, until the scale of tech assholery shifted wildly for the worse, and he switched to legacy building mode.
What do you mean by "persona"? Do you mean he's not really giving money away?
For instance if there was a homeless person on my street and I figured that giving them $500 would have good odds of having them OD and no longer being on my street... what looks like a charitable act very much isn't. So while it would contribute to a charitable persona it wouldn't reflect personality.
Some guys, like Gates, seemed to have extremely opinionated views on what Microsoft products should have been like. That should be a given, as he was the co-founder and CEO, but when you see older footage of him, he has (had?) this "This doesn't make sense to me, so it is shit" way of seeing things. He also seemed to have a typical brutally honest way of reviewing stuff, which can make one come off as very abrasive.
Can't remember where I read it, but there was this psychology paper that studied elite performers, those that were considered to be at the very top of their game (sports, business, art, culinary, etc.) - and toxic/abrasive leadership is just more accepted, because the top performers strive for perfection, no mater the cost. Their subordinates and co-workers just consider it "tough love", instead of abusive behavior.