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.
No, the highest temperature I have ever recorded was 76°C. Without fan, and using thermal pads to connect the case to components.
But I hate high numbers, excessive heat already shortened a Pi lifetime here, since then I am very cautious about that.