I have been looking for a window film that reflects the heat but allows enough light through. My windows have enough factory tint already. Most window film goes on the inside. I think, to reject heat, it must be installed on the outside. Like you said, even the window frames are hot. I found this.
There is only one sentence that says it is possible to install on the outside.
"Window film is to be applied on the inside of your window unless specified otherwise."
BDF NSN70 Window Film Transparent Ultra High Heat Rejection & UV Cut NSN 70 (Very Light) - 36in X 14ft
https://www.amazon.com/gp/product/B0...3200_439081400
The only other thing to do would be to install awnings over the windows that dont have them.