Question re: high-wind area deck/pergola

Hi, all! I’m building a deck out back with my dad, and we’re at the digging-holes stage. It’ll be about 10’x35’ along the back of the house, freestanding (not attached to the house) and the surface will be about a foot to 18 inches off the ground. We’re tying into footers that the previous owners dug and installed, plus putting in more of our own since theirs are 10 ft apart. My question is, I’d like to have a pergola for shade over this deck, which led my stepmom to suggest sinking treated 4x4s in 2ft of concrete for stability in high winds. The wind is wretched and brutal here, with gusts that peel off roofs and tip semis. I know how this sub feels about burying posts, and I read burying posts in concrete is a no-no if they’re load-bearing. I guess I’m wondering if there’s a type of base/tie for the bases of the posts that are better in high winds? Or does her idea of sinking the 4x4s in concrete have merit? I AM planning a lot of diagonal bracing.