I use mostly the passive cooling
Geekworm P173 aluminum case with Gelid GP-UL Ultimate thermal pads (those particular thermal pads are not necessarily needed but I had them anyway, it's fine to use the case's provided ones, too).
Passively cooled with this P173 case my Raspi 4Bs rarely exceed 50-55°C under load.
To be safe in summer heat and generally have a lower temp even under high load I upgraded this case with some forced airflow by a Noctua NF-A5x25 5V fan which I run on 3.3V from appropriate GPIO pins. At 3.3V this fan is barely perceptible even on close distance and the Raspi doesn't go over ~45°C under stress test with full load on all cores.
Average temps of my Raspi nodes with this setup is somewhere around 33°C and maybe 36-38°C in summer heat.
