My cart will be ten years old this summer, I've had the basic fold-down windshield the whole time and that's all they offered then. It will probably give you as much air as you can stand when it's folded. Some people will buy a pop-in screen, you can find them at Ace for about $20, I've never had any bug problems when it's folded.
My neighbor who I use to sometimes ride with before Covid to the gold course has these slots with the sliding covers. I don't really find much air coming through, if it does, it's not up by your face. He still folds down his windshield when it's hot and that blocks the slots anyway.
I've seen carts that have almost a 3 piece windshield, whereas the bottom will pop forward. That might work good, with the air flowing over the cowling and maybe up toward your face, you could keep the top closed and still have air. I haven't spoken to anyone that has one.
I also have a 12v fan that provides some air when you're sitting still. I bought it on the Home Depot website for $30 and run the wire down to the 12v Cig adapter plug.