Earlier quoted context omitted.
I did an article on the topic after the Pi firmware update made the situation a lot better. A bare Pi is okay without a fan, but if you want it in a case, the Flirc case is your best option (IMO): https://www.jeffgeerling.com/blog/2019/best-way-keep-your-co...
For my use case, I need access to the GPIO pins. The blurb on the Flirc says that access is possible but I don't see any opening. Can you confirm that GPIO access I possible?
The gpio access requires a header cable routed out a slot in the base of the case.
I have several pi in flirc cases, one is a pihole and one runs CI jobs (slowly) for PhotoStructure, and they don't get too hot even under sustained cpu load.
Flirc cases are great.