For Raspberry Pi4 continuous selfhosted server operations: with and without case fan. This graph show a 20°C decrease, with a slow rpm fan.
The metal case has thermal stickers to reach for main components on both sides, and the fan is what I have in scrap parts, totally not for that case but pushes a lot of air with low noise compared to screaming mini cpu fans.
I’ve got the same Geekworm cases for all my Raspberries. Added some extra thermal pads in some strategic places and have them all without any active cooling at room temperature (20-21℃). They barely go over 55℃:
The 3B+ has soft-throttling (can be disabled) starting at 60℃, full throttling at 70°C. The 4 starts throttling at 80℃ and the 5 at 85℃. So, with that completely passive cooling I’m still far away from these margins. No need for any moving parts that will make noise at some point in the future.
Also, since the cases have ribs on both sides, I have my Pis standing upright to hopefully make use of the stack effect - which might contribute to the slightly lower than OP’s values.