OP, Congratulations.
You seem sensible but there's one thing you said that stood out to me. You wrote, "And yes, I do 3 -4 days of volunteering, I'd probably die of boredom if I didn't".
You have to think out of the box. With the money you have you shouldn't have to fulfill yourself with designer handbags and holidays. There's no need to risk taking volunteering slots away from people who need them because they are lonely or have no other choice of what they can do.
You are financially capable of starting your own charity if that's what you're into.
Although I didn't win the lottery (yet) this is what I have done with my time and $.
I had built a large building, paid for it outright, and started a business for my descendants to either carry on or start others businesses or projects. It's versatile. I also had lots and lots of land and so on some of it, I planted hundreds trees/shrubs (decades ago) and now have a lovely park full of unusual and rare (for the area) trees. It's filled with wildlife and birds. My family will enjoy it for years to come.
I'm not into fancy handbags, holidays and only hoping my descendants to be good little employees/workers for someone else.
I also write - research things I'm interested in. I haven't been employed by anyone for about 40 years and I've never been bored a day in my life.
Don't leave money to strangers at a charity to decide what to do with it. You make the world a better place while you are still alive.