Painted or Bare Aluminum Roof?

Did you notice excessive heat build up with the bare metal vs painted?

Mine has been bare aluminum, I don't think it has much effect. When it is hot out, it is hot inside.
On another subject, I recently had an eye opening experience in the shed I built during the pandemic. I had planned on insulating with foil faced rigid foam board, and had a few pieces that I hadn't installed. I went in one day to get a tool and saw "sawdust" on a shelf at eye level. Then I heard something that sounded like light rainfall. Looking around I realized that there were piles of "sawdust" all over the shed. Climbed the ladder to the loft and found carpenter ants-thousands of them! The little buggers had nested inside the foil. I checked online to see if others had had this happen and it is common, causing unbelievable damage in buildings. I had some of that blue styrofoam board as well and they hadn't touched it. I'm so glad I never got around to installing the foil faced stuff in the walls! The ants don't eat the foam, it is just that they can easily tunnel into it and it obviously provides a warm place for the nests.

Even when it is really hot, movement of air is helpful. A good roof vent fan is the best way to create cross ventilation if you do not have air conditioning. A couple of 12vdc fans strategically placed near sleeping or sitting places also helps. We lived on a boat in SW Florida for 10 years. The first year without AC. There were many nights when we'd find ourselves outside on the dock hosing ourselves down at 3am. I finally got the largest capacity 110vac air conditioner I could find. We'd run it for an hour or two before bedtime and life was good again! We rarely stay in campgrounds with hookups, and I can't sleep with a noisy air conditioner. Sometimes the drone of the fans provides "white noise" that drowns out the sounds of noisy neighbors.