So how about go, earn your own millions by 'making series about spaghetti' and then donate it all? No? Easier to 'donate' somebody else's money, I'm sure.
And why Meghan? Why not Jeff Bezos? Elon Musk? Yes, I'm sure they made token contributions to charity to appear good and use the tax breaks, but they're both not known philanthropists and Meghan is a pauper compared to them (and similar). Hell, Bezos doesn't even need to donate anything, he just needs to pay appropriate tax on his endeavours and that would help the economy considerably. Yet he chose to buy a massive fuck off diamond to his fiance and go to a space trip (and whatever the hell else he does).
Anyway. If I'd be filthy rich (more than Meghan) - I wouldn't do anything. I'd sell my business, enjoy my family, help my family in various ways, buy multiple properties in gorgeous corners of the world and travel the world continuously as that's my favourite thing to do. I travel a lot already, but I would do it more and in more luxurious ways.
I'm not rich, but comfortable and all I have I've earned myself. So others are welcome to do the same. I don't see why should I share what's mine - nobody gave it to me, I earned it. I don't volunteer, engage in charity and/or donate my money and nor would I, if I'd be rich-rich. I'd leave it to my child and brother (if he survives me) instead.
'Humanitarian issues' don't concern me. AT ALL.
Meghan is doing nothing wrong. Haven't watched her show (might do), but you're also entitled to skip it, if it annoys you so much. Plenty of massive Hollywood stars are hugely rich and still make films. They don't have to, they're certainly wealthy enough, but presumably they want to. So if 'cooking spaghetti' on screen makes Meghan happy - good for her.