Note that the main issue here is to avoid cpu throttling due to excessive heat. IIRC you can allow a higher cut-off temp (100ºC instead 77ºC) by setting a config parameter. This will possibly reduce the chip lifespan from whatever it is to decades! But make sure no one can accidentally touch the chip.

I have one case with a fan and one case where part of the case body attaches to the chip top with thermal goop. The fan works better.