I got this one on amazon that worked great! However, it was not purchased with "style" in mind - just that it's big, has a wide brim that covers my neck, and fits my massive dome. I wear an 8 or an 8(1/8) for fitted caps a reference, and this one fits well.
As for looking goofy... it's a sun-hat. It's going to always look goofy!
On hot days back home in UT, they would let us wade in the pool as we kept watch. Helped a little. Also, big, goofy sun hats are a must.
I'm not sure if there was a cooling effect since it was 2 years ago. But I'm sure if you start sweating or wet it before putting it on, there would be an effect.
I bought this one
This is not the most attractive. But it has a wide brim, and you can tie it beneath your chin to secure it. It’s what I use when I exercise outdoors.
I got this one on prime for $20. It fits amazing and after you get used to it being so wide you'll love it! :)
O'Neill Men's Sonoma Prints Straw Hat, Naturl1, One Size https://www.amazon.com/dp/B00NIVAEG8/ref=cm_sw_r_cp_apip_2WEixP3qBowtE
Found this while searching for a hat to wear out in the sun. Here is the hat in question.