Ours is quite big and faces east. One year, while we were away on holiday, there was a short hot spell when temperatures at home reached the low 30s. We got back to find the wax had melted on an old table and dripped onto the wood laminate floor - which had lifted in several places. Also the nylon string holding a picture up had melted and the picture was smashed on the floor. The books in the bookcase were still quite warm in the middle despite the heat wave having passed several days previously! All this with a polycarb roof with special stuff layered inside which was supposed to keep out the heat, side windows left securely with a slit opening - but there was no wind, so no draft - and heat reflecting blinds on the side windows.
We investigated several options. Automatic opening roof lights, stick on film (only keeps out 10%), blinds and several sorts of solid roof. We decided on a mid range solid roof with non-opening skylights each end in the hips (can’t be opening or have blinds due to being a weird shape). It’s made such a difference. It still gets hot when closed up, but not nearly as hot as previously and stays warmer in winter so we use it far more. Strangely the room seems just as light and the kitchen, which looks into it, gets more light from the skylight.