Its actually very easy to cool down a PC without case, much easier than people think. Mostly because of the "infinite" amount of air source to cool down things. Obviously this should not be 30C, but even at that level it will be easier than with a case.
Note that this is only CPU, RAM dimms that don't need any active cooling, SAS card that NEEDS active cooling, hence the fan, and then the SAS SSD disks that don't need any active cooling probably, but I am going to do it anyway, to keep their wearing off lower (yes SSDs and NVMes wear off faster the hotter they are operating at, resulting on sooner breakdowns).
Once I get some numbers, I will share around here.