I have been experimenting with Julia on the RPi 4B. You don’t have to use a fan, however, there are passive heatsinking “cases” which do a very good job. The heatsink will get very warm!
The advantage of the RPi 4B is that it will use the ARM64 binary just fine. So I can use the latest and greatest version, which is currently 1.4.1 by simply downloading the binary into the RPi 4B. You can install Ubuntu Server, and then add a desktop if you wish.
I prefer Xubuntu.
Now I also wanted a much lower power option. Raspberry Pi Zero worked for my simple project, however, the latest binary will not work due to having an incompatible 32 bit ARM. I installed the Raspian repository version, which is 1.0.3. Fortunately with my simple project this worked perfectly!
My project is a SPI interface driver. I wrote a simple shared library in C, and I use the ccall function to drive the RPi SPI interface from Julia. Yes, I could do the whole thing in C, but then I would not have a scripting language and a REPL.
Raspberry Pi + Julia maybe not a serious embedded platform, but it is a lot of fun!